diff --git a/openvidu-getaroom/web/app.js b/openvidu-getaroom/web/app.js
index cc17beb8..7805b77f 100644
--- a/openvidu-getaroom/web/app.js
+++ b/openvidu-getaroom/web/app.js
@@ -1,21 +1,22 @@
-var OV;
-var session;
-var publisher;
-var sessionId;
-var audioEnabled = true;
-var videoEnabled = true;
-var numOfVideos = 0;
+var OV;						// OpenVidu object to initialize a session
+var session;				// Session object where the user will connect
+var publisher;				// Publisher object which the user will publish
+var sessionId;				// Unique identifier of the session
+var audioEnabled = true;	// True if the audio track of publisher is active
+var videoEnabled = true;	// True if the video track of publisher is active
+var numOfVideos = 0;		// Keeps track of the number of videos that are being shown
 
 
 // Check if the URL already has a room
 window.addEventListener('load', function () {
-	sessionId = window.location.hash;
+	sessionId = window.location.hash; // For 'https://myurl/#roomId', sessionId would be '#roomId'
 	if (sessionId) {
-		// The URL has a session id
+		// The URL has a session id. Join the room right away
 		console.log("Joining to room " + sessionId);
 		showSessionHideJoin();
 		joinRoom(sessionId);
 	} else {
+		// The URL has not a session id. Show welcome page
 		showJoinHideSession();
 	}
 });
@@ -38,11 +39,11 @@ function joinRoom(sessionId) {
 
 	// --- 1) Get an OpenVidu object and init a session with a sessionId ---
 
-	// Init OpenVidu object
 	OV = new OpenVidu();
 
-	// We will join the video-call "sessionId". This parameter must start with the URL of OpenVidu Server, with secure WebSocket protocol ('wss://')
-	session = OV.initSession("wss://" + location.hostname + ":8443/" + sessionId + '?secret=MY_SECRET');
+	// We will join the video-call "sessionId". As there's no server, this parameter must start with the URL of 
+	// OpenVidu Server (with secure websocket protocol: "wss://") and must include the OpenVidu secret at the end
+	session = OV.initSession("wss://" + location.hostname + ":8443/" + sessionId + "?secret=MY_SECRET");
 
 
 	// --- 2) Specify the actions when events take place ---
@@ -51,6 +52,7 @@ function joinRoom(sessionId) {
 	session.on('streamCreated', function (event) {
 		// Subscribe to the Stream to receive it. HTML video will be appended to element with 'subscriber' id
 		var subscriber = session.subscribe(event.stream, 'videos');
+		// When the new video is added to DOM, update the page layout to fit one more participant
 		subscriber.on('videoElementCreated', function (event) {
 			numOfVideos++;
 			updateLayout();
@@ -59,6 +61,7 @@ function joinRoom(sessionId) {
 
 	// On every new Stream destroyed...
 	session.on('streamDestroyed', function (event) {
+		// Update the page layout
 		numOfVideos--;
 		updateLayout();
 	});
@@ -66,8 +69,7 @@ function joinRoom(sessionId) {
 
 	// --- 3) Connect to the session ---
 
-	// 'token' param irrelevant when using insecure version of OpenVidu. Second param will be received by every user
-	// in Stream.connection.data property, which will be appended to DOM as the user's nickname
+	// Remember 'userId' param (usually called 'token') is irrelevant when using the insecure version of OpenVidu
 	session.connect(userId, function (error) {
 
 		// If the connection is successful, initialize a publisher and publish to the session
@@ -82,9 +84,10 @@ function joinRoom(sessionId) {
 			});
 
 			publisher.on('videoElementCreated', function (event) {
+				// When your own video is added to DOM, update the page layout to fit it
 				numOfVideos++;
 				updateLayout();
-				$(event.element).prop('muted', true);
+				$(event.element).prop('muted', true); // Mute local video
 			});
 
 			// --- 5) Publish your stream ---
@@ -96,9 +99,11 @@ function joinRoom(sessionId) {
 		}
 	});
 
+	// Update the URL shown in the browser's navigation bar to show the session id
 	var pathname = (location.pathname.slice(-1) === "/" ? location.pathname : location.pathname+"/");
 	window.history.pushState("", "", pathname + sessionId);
 
+	// Auxiliary methods to show the session's view
 	showSessionHideJoin();
 	initializeSessionView();
 
@@ -107,7 +112,7 @@ function joinRoom(sessionId) {
 
 
 function leaveRoom() {
-
+	
 	// --- 6) Leave the session by calling 'disconnect' method over the Session object ---
 	session.disconnect();
 	
diff --git a/openvidu-js-java/src/main/java/io/openvidu/js/java/LoginController.java b/openvidu-js-java/src/main/java/io/openvidu/js/java/LoginController.java
index 055978e4..2445875e 100644
--- a/openvidu-js-java/src/main/java/io/openvidu/js/java/LoginController.java
+++ b/openvidu-js-java/src/main/java/io/openvidu/js/java/LoginController.java
@@ -46,15 +46,18 @@ public class LoginController {
 	public ResponseEntity<Object> login(@RequestBody String userPass, HttpSession httpSession) throws ParseException {
 
 		System.out.println("Logging in | {user, pass}=" + userPass);
+		// Retrieve params from POST body
 		JSONObject userPassJson = (JSONObject) new JSONParser().parse(userPass);
 		String user = (String) userPassJson.get("user");
 		String pass = (String) userPassJson.get("pass");
 
-		if (login(user, pass)) {
-			System.out.println("'" + user + "' has logged in");
+		if (login(user, pass)) { // Correct user-pass
+			// Validate session and return OK 
+			// Value stored in HttpSession allows us to identify the user in future requests
 			httpSession.setAttribute("loggedUser", user);
 			return new ResponseEntity<>(HttpStatus.OK);
-		} else {
+		} else { // Wrong user-pass
+			// Invalidate session and return error
 			httpSession.invalidate();
 			return new ResponseEntity<>("User/Pass incorrect", HttpStatus.UNAUTHORIZED);
 		}
diff --git a/openvidu-js-java/src/main/java/io/openvidu/js/java/SessionController.java b/openvidu-js-java/src/main/java/io/openvidu/js/java/SessionController.java
index 5cc1ccfc..a5e9daf3 100644
--- a/openvidu-js-java/src/main/java/io/openvidu/js/java/SessionController.java
+++ b/openvidu-js-java/src/main/java/io/openvidu/js/java/SessionController.java
@@ -51,10 +51,18 @@ public class SessionController {
 		System.out.println("Getting sessionId and token | {sessionName}=" + sessionNameParam);
 
 		JSONObject sessionJSON = (JSONObject) new JSONParser().parse(sessionNameParam);
+	
+		// The video-call to connect ("TUTORIAL")
 		String sessionName = (String) sessionJSON.get("session");
+		
+		// Role associated to this user
 		OpenViduRole role = LoginController.users.get(httpSession.getAttribute("loggedUser")).role;
+		
+		// Optional data to be passed to other users when this user connects to the video-call
+		// In this case, a JSON with the value we stored in the HttpSession object on login
 		String serverData = "{\"serverData\": \"" + httpSession.getAttribute("loggedUser") + "\"}";
 
+		// Build tokenOptions object with the serverData and the role
 		TokenOptions tokenOptions = new TokenOptions.Builder().data(serverData).role(role).build();
 
 		JSONObject responseJson = new JSONObject();
@@ -63,16 +71,25 @@ public class SessionController {
 			// Session already exists: return existing sessionId and a new token
 			System.out.println("Existing session " + sessionName);
 			try {
+			
+				// Get the existing sessionId from our collection with 
+				// the sessionName param ("TUTORIAL")
 				String sessionId = this.mapSessions.get(sessionName).getSessionId();
+				// Generate a new token with the recently created tokenOptions
 				String token = this.mapSessions.get(sessionName).generateToken(tokenOptions);
-
+				
+				// Update our collection storing the new token
 				this.mapSessionIdsTokens.get(sessionId).put(token, role);
-
+				
+				// Prepare the response with the sessionId and the token
 				responseJson.put(0, sessionId);
 				responseJson.put(1, token);
-
+				
+				// Return the response to the client
 				return new ResponseEntity<>(responseJson, HttpStatus.OK);
+				
 			} catch (Exception e) {
+				// If error generate an error message and return it to client
 				return getErrorResponse(e);
 			}
 
@@ -80,19 +97,28 @@ public class SessionController {
 			// New session: return a new sessionId and token
 			System.out.println("New session " + sessionName);
 			try {
+
+				// Create a new OpenVidu Session
 				Session session = this.openVidu.createSession();
+				// Get the sessionId
 				String sessionId = session.getSessionId();
+				// Generate a new token with the recently created tokenOptions
 				String token = session.generateToken(tokenOptions);
 
+				// Store the session and the token in our collections
 				this.mapSessions.put(sessionName, session);
 				this.mapSessionIdsTokens.put(sessionId, new ConcurrentHashMap<>());
 				this.mapSessionIdsTokens.get(sessionId).put(token, role);
 
+				// Prepare the response with the sessionId and the token
 				responseJson.put(0, sessionId);
 				responseJson.put(1, token);
 
+				// Return the response to the client
 				return new ResponseEntity<>(responseJson, HttpStatus.OK);
+				
 			} catch (Exception e) {
+				// If error generate an error message and return it to client
 				return getErrorResponse(e);
 			}
 		}
@@ -109,30 +135,36 @@ public class SessionController {
 		}
 		System.out.println("Removing user | {sessionName, token}=" + sessionNameToken);
 
+		// Retrieve the params from BODY
 		JSONObject sessionNameTokenJSON = (JSONObject) new JSONParser().parse(sessionNameToken);
 		String sessionName = (String) sessionNameTokenJSON.get("sessionName");
 		String token = (String) sessionNameTokenJSON.get("token");
 
+		// If the session exists ("TUTORIAL" in this case)
 		if (this.mapSessions.get(sessionName) != null) {
 			String sessionId = this.mapSessions.get(sessionName).getSessionId();
 
 			if (this.mapSessionIdsTokens.containsKey(sessionId)) {
+				// If the token exists
 				if (this.mapSessionIdsTokens.get(sessionId).remove(token) != null) {
 					// User left the session
 					if (this.mapSessionIdsTokens.get(sessionId).isEmpty()) {
-						// Last user left the session
+						// Last user left: session must be removed
 						this.mapSessions.remove(sessionName);
 					}
 					return new ResponseEntity<>(HttpStatus.OK);
 				} else {
+					// The TOKEN wasn't valid
 					System.out.println("Problems in the app server: the TOKEN wasn't valid");
 					return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);
 				}
 			} else {
+				// The SESSIONID wasn't valid
 				System.out.println("Problems in the app server: the SESSIONID wasn't valid");
 				return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);
 			}
 		} else {
+			// The SESSION does not exist
 			System.out.println("Problems in the app server: the SESSION does not exist");
 			return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);
 		}
diff --git a/openvidu-js-java/src/main/resources/static/app.js b/openvidu-js-java/src/main/resources/static/app.js
index 1814000c..f55a7016 100644
--- a/openvidu-js-java/src/main/resources/static/app.js
+++ b/openvidu-js-java/src/main/resources/static/app.js
@@ -73,7 +73,7 @@ function joinSession() {
 						};
 						initMainVideo(event.element, userData);
 						appendUserData(event.element, userData);
-						$(event.element).prop('muted', true);
+						$(event.element).prop('muted', true); // Mute local video
 					});
 
 
@@ -116,17 +116,18 @@ function leaveSession() {
 
 
 
-/* APPLICATION BACKEND METHODS */
+/* APPLICATION REST METHODS */
 
 function logIn() {
-	var user = $("#user").val();
-	userName = user;
-	var pass = $("#pass").val();
-	var jsonBody = JSON.stringify({
+	var user = $("#user").val(); // Username
+	var pass = $("#pass").val(); // Password
+	var jsonBody = JSON.stringify({ // Body of POST request
 		'user': user,
 		'pass': pass
 	});
 
+	userName = user;
+
 	httpRequest('POST', 'api-login/login', jsonBody, 'Login WRONG', function successCallback(response) {
 		console.warn(userName + ' login');
 		$("#name-user").text(user);
@@ -147,26 +148,30 @@ function logOut() {
 }
 
 function getSessionIdAndToken(callback) {
-	nickName = $("#participantName").val();
-	sessionName = $("#sessionName").val();
-	var jsonBody = JSON.stringify({
+	sessionName = $("#sessionName").val(); // Video-call chosen by the user
+	nickName = $("#participantName").val(); // Nickname chosen by the user
+	
+	var jsonBody = JSON.stringify({ // Body of POST request
 		'session': sessionName
 	});
 
+	// Send POST request
 	httpRequest('POST', 'api-sessions/get-sessionid-token', jsonBody, 'Request of SESSIONID and TOKEN gone WRONG:', function successCallback(response) {
-		sessionId = response[0];
-		token = response[1];
+		sessionId = response[0]; // Get sessionId from response
+		token = response[1]; // Get token from response
 		console.warn('Request of SESSIONID and TOKEN gone WELL (SESSIONID:' + sessionId + ", TOKEN:" + token + ")");
-		callback();
+		callback(); // Continue the join operation
 	});
 }
 
 function removeUser() {
+	// Body of POST request with the name of the session and the token of the leaving user
 	var jsonBody = JSON.stringify({
 		'sessionName': sessionName,
 		'token': token
 	});
 
+	// Send POST request
 	httpRequest('POST', 'api-sessions/remove-user', jsonBody, 'User couldn\'t be removed from session', function successCallback(response) {
 		console.warn(userName + " correctly removed from session");
 	});
@@ -195,7 +200,7 @@ function httpRequest(method, url, body, errorMsg, callback) {
 	}
 }
 
-/* APPLICATION BACKEND METHODS */
+/* APPLICATION REST METHODS */
 
 
 
diff --git a/openvidu-js-node/public/app.js b/openvidu-js-node/public/app.js
index 1814000c..a5f9437e 100644
--- a/openvidu-js-node/public/app.js
+++ b/openvidu-js-node/public/app.js
@@ -27,11 +27,11 @@ function joinSession() {
 			// Subscribe to the Stream to receive it
 			// HTML video will be appended to element with 'video-container' id
 			var subscriber = session.subscribe(event.stream, 'video-container');
-
+			
 			// When the HTML video has been appended to DOM...
 			subscriber.on('videoElementCreated', function (event) {
-
-				// Add a new HTML element for the user's name and nickname over its video
+			
+				// Add a new <p> element for the user's name and nickname just below its video
 				appendUserData(event.element, subscriber.stream.connection);
 			});
 		});
@@ -42,6 +42,7 @@ function joinSession() {
 			removeUserData(event.stream.connection);
 		});
 
+
 		// --- 3) Connect to the session passing the retrieved token and some more data from
 		//         the client (in this case a JSON with the nickname chosen by the user) ---
 
@@ -73,7 +74,7 @@ function joinSession() {
 						};
 						initMainVideo(event.element, userData);
 						appendUserData(event.element, userData);
-						$(event.element).prop('muted', true);
+						$(event.element).prop('muted', true);  // Mute lcoal video
 					});
 
 
@@ -116,18 +117,19 @@ function leaveSession() {
 
 
 
-/* APPLICATION BACKEND METHODS */
+/* APPLICATION REST METHODS */
 
 function logIn() {
-	var user = $("#user").val();
-	userName = user;
-	var pass = $("#pass").val();
-	var jsonBody = JSON.stringify({
+	var user = $("#user").val(); // Username
+	var pass = $("#pass").val(); // Password
+	var jsonBody = JSON.stringify({ // Body of POST request
 		'user': user,
 		'pass': pass
 	});
 
-	httpRequest('POST', 'api-login/login', jsonBody, 'Login WRONG', function successCallback(response) {
+	userName = user;
+
+	httpRequest('POST', '/api-login/login', jsonBody, 'Login WRONG', function successCallback(response){ // Send POST request
 		console.warn(userName + ' login');
 		$("#name-user").text(user);
 		$("#not-logged").hide();
@@ -147,26 +149,29 @@ function logOut() {
 }
 
 function getSessionIdAndToken(callback) {
-	nickName = $("#participantName").val();
-	sessionName = $("#sessionName").val();
-	var jsonBody = JSON.stringify({
+	sessionName = $("#sessionName").val(); // Video-call chosen by the user
+	nickName = $("#participantName").val(); // Nickname chosen by the user
+	var jsonBody = JSON.stringify({ // Body of POST request
 		'session': sessionName
 	});
 
+	// Send POST request
 	httpRequest('POST', 'api-sessions/get-sessionid-token', jsonBody, 'Request of SESSIONID and TOKEN gone WRONG:', function successCallback(response) {
-		sessionId = response[0];
-		token = response[1];
+		sessionId = response[0]; // Get sessionId from response
+		token = response[1]; // Get token from response
 		console.warn('Request of SESSIONID and TOKEN gone WELL (SESSIONID:' + sessionId + ", TOKEN:" + token + ")");
-		callback();
+		callback(); // Continue the join operation
 	});
 }
 
 function removeUser() {
+	// Body of POST request with the name of the session and the token of the leaving user
 	var jsonBody = JSON.stringify({
 		'sessionName': sessionName,
 		'token': token
 	});
 
+	// Send POST request
 	httpRequest('POST', 'api-sessions/remove-user', jsonBody, 'User couldn\'t be removed from session', function successCallback(response) {
 		console.warn(userName + " correctly removed from session");
 	});
@@ -195,7 +200,7 @@ function httpRequest(method, url, body, errorMsg, callback) {
 	}
 }
 
-/* APPLICATION BACKEND METHODS */
+/* APPLICATION REST METHODS */
 
 
 
diff --git a/openvidu-js-node/server.js b/openvidu-js-node/server.js
index d5b7af84..c64b697f 100644
--- a/openvidu-js-node/server.js
+++ b/openvidu-js-node/server.js
@@ -60,15 +60,17 @@ var users = [{
 }];
 
 
-// Environment variables
+// Environment variable: URL where our OpenVidu server is listening
 var OPENVIDU_URL = process.argv[2];
+// Environment variable: secret shared with our OpenVidu server
 var OPENVIDU_SECRET = process.argv[3];
 
-// OpenVidu object
+// OpenVidu object to ask openvidu-server for sessionId and token
 var OV = new OpenVidu(OPENVIDU_URL, OPENVIDU_SECRET);
 
-// Objects for storing active sessions and users
+// Collection to pair session names and OpenVidu Session objects
 var mapSessionNameSession = {};
+// Collection to pair sessionId's (identifiers of Session objects) and tokens
 var mapSessionIdTokens = {};
 
 /* CONFIGURATION */
@@ -79,15 +81,20 @@ var mapSessionIdTokens = {};
 
 // Login
 app.post('/api-login/login', function (req, res) {
+    
+    // Retrieve params from POST body
     var user = req.body.user;
     var pass = req.body.pass;
     console.log("Logging in | {user, pass}={" + user + ", " + pass + "}");
 
-    if (login(user, pass)) {
+    if (login(user, pass)) { // Correct user-pass
+        // Validate session and return OK 
+        // Value stored in req.session allows us to identify the user in future requests
         console.log("'" + user + "' has logged in");
         req.session.loggedUser = user;
         res.status(200).send();
-    } else {
+    } else { // Wrong user-pass
+        // Invalidate session and return error
         console.log("'" + user + "' invalid credentials");
         req.session.destroy();
         res.status(401).send('User/Pass incorrect');
@@ -107,22 +114,40 @@ app.post('/api-sessions/get-sessionid-token', function (req, res) {
         req.session.destroy();
         res.status(401).send('User not logged');
     } else {
+        // The video-call to connect ("TUTORIAL")
         var sessionName = req.body.session;
+    
+        // Role associated to this user
         var role = users.find(u => (u.user === req.session.loggedUser)).role;
+    
+        // Optional data to be passed to other users when this user connects to the video-call
+        // In this case, a JSON with the value we stored in the req.session object on login
         var serverData = '{"serverData": "' + req.session.loggedUser + '"}';
         console.log("Getting sessionId and token | {sessionName}={" + sessionName + "}");
-
+    
+        // Build tokenOptions object with the serverData and the role
         var tokenOptions = new TokenOptions.Builder()
             .data(serverData)
             .role(role)
             .build();
 
         if (mapSessionNameSession[sessionName]) {
+            // Session already exists: return existing sessionId and a new token
             console.log('Existing session ' + sessionName);
+            
+            // Get the existing Session from the collection
             var mySession = mapSessionNameSession[sessionName];
+            
+            // Generate a new token asynchronously with the recently created tokenOptions
             mySession.generateToken(tokenOptions, function (token) {
+                
+                // Get the existing sessionId
                 var sessionId = mySession.getSessionId();
+                
+                // Store the new token in the collection of tokens
                 mapSessionIdTokens[sessionId].push(token);
+                
+                // Return the sessionId and token to the client
                 console.log('SESSIONID: ' + sessionId);
                 console.log('TOKEN: ' + token);
                 res.status(200).send({
@@ -130,17 +155,28 @@ app.post('/api-sessions/get-sessionid-token', function (req, res) {
                     1: token
                 });
             });
-        } else {
+        } else { // New session: return a new sessionId and a new token
+            // Create a new OpenVidu Session
             console.log('New session ' + sessionName);
             var mySession = OV.createSession();
+            
+            // Get the sessionId asynchronously
             mySession.getSessionId(function (sessionId) {
+                
+                // Store the new Session in the collection of Sessions
                 mapSessionNameSession[sessionName] = mySession;
+                // Store a new empty array in the collection of tokens
                 mapSessionIdTokens[sessionId] = [];
-
+                
+                // Generate a new token asynchronously with the recently created tokenOptions
                 mySession.generateToken(tokenOptions, function (token) {
+                    
+                    // Store the new token in the collection of tokens
                     mapSessionIdTokens[sessionId].push(token);
                     console.log('SESSIONID: ' + sessionId);
                     console.log('TOKEN: ' + token);
+                    
+                    // Return the sessionId and token to the client
                     res.status(200).send({
                         0: sessionId,
                         1: token
@@ -157,16 +193,21 @@ app.post('/api-sessions/remove-user', function (req, res) {
         req.session.destroy();
         res.status(401).send('User not logged');
     } else {
+        // Retrieve params from POST body
         var sessionName = req.body.sessionName;
         var token = req.body.token;
         console.log('Removing user | {sessionName, token}={' + sessionName + ", " + token + '}');
-        
+
+        // If the session exists ("TUTORIAL" in this case)
         var mySession = mapSessionNameSession[sessionName];
         if (mySession) {
             var tokens = mapSessionIdTokens[mySession.getSessionId()];
             if (tokens) {
                 var index = tokens.indexOf(token);
-                if (index !== -1) { // User left the session
+                
+                // If the token exists
+                if (index !== -1) {
+                    // Token removed!
                     tokens.splice(index, 1);
                     console.log(sessionName + ': ' + mapSessionIdTokens[mySession.getSessionId()].toString());
                 } else {
@@ -174,7 +215,8 @@ app.post('/api-sessions/remove-user', function (req, res) {
                     console.log(msg);
                     res.status(500).send(msg);
                 }
-                if (mapSessionIdTokens[mySession.getSessionId()].length == 0) { // Last user left the session
+                if (mapSessionIdTokens[mySession.getSessionId()].length == 0) {
+                    // Last user left: session must be removed
                     console.log(sessionName + ' empty!');
                     delete mapSessionNameSession[sessionName];
                 }
diff --git a/openvidu-mvc-java/src/main/java/io/openvidu/mvc/java/LoginController.java b/openvidu-mvc-java/src/main/java/io/openvidu/mvc/java/LoginController.java
index 812f1748..00ed026d 100644
--- a/openvidu-mvc-java/src/main/java/io/openvidu/mvc/java/LoginController.java
+++ b/openvidu-mvc-java/src/main/java/io/openvidu/mvc/java/LoginController.java
@@ -49,20 +49,30 @@ public class LoginController {
 
 	@RequestMapping(value = "/dashboard", method = { RequestMethod.GET, RequestMethod.POST })
 	public String login(@RequestParam(name = "user", required = false) String user,
-			@RequestParam(name = "pass", required = false) String pass, Model model, HttpSession httpSession) {
+				@RequestParam(name = "pass", required = false) String pass,
+				Model model, HttpSession httpSession) {
 
+		// Check if the user is already logged in
 		String userName = (String) httpSession.getAttribute("loggedUser");
-		if (userName != null) { // User is already logged
+		if (userName != null) { 
+			// User is already logged. Immediately return dashboard
 			model.addAttribute("username", userName);
 			return "dashboard";
 		}
-		System.out.println("Logging in | {user, pass}={" + user + ", " + pass + "}");
-		if (login(user, pass)) { // User is logging in
-			System.out.println("'" + user + "' has logged in");
+		
+		// User wasn't logged and wants to
+		if (login(user, pass)) { // Correct user-pass
+			
+			// Validate session and return OK 
+			// Value stored in HttpSession allows us to identify the user in future requests
 			httpSession.setAttribute("loggedUser", user);
 			model.addAttribute("username", user);
+			
+			// Return dashboard.html template
 			return "dashboard";
-		} else {
+			
+		} else { // Wrong user-pass
+			// Invalidate session and redirect to index.html
 			httpSession.invalidate();
 			return "redirect:/";
 		}
diff --git a/openvidu-mvc-java/src/main/java/io/openvidu/mvc/java/SessionController.java b/openvidu-mvc-java/src/main/java/io/openvidu/mvc/java/SessionController.java
index 24299aa9..5d4c3b60 100644
--- a/openvidu-mvc-java/src/main/java/io/openvidu/mvc/java/SessionController.java
+++ b/openvidu-mvc-java/src/main/java/io/openvidu/mvc/java/SessionController.java
@@ -20,12 +20,17 @@ import io.openvidu.java.client.TokenOptions;
 @Controller
 public class SessionController {
 
-	OpenVidu openVidu;
+	// OpenVidu object to ask openvidu-server for sessionId and token
+	private OpenVidu openVidu;
 
+	// Collection to pair session names and OpenVidu Session objects
 	private Map<String, Session> mapSessions = new ConcurrentHashMap<>();
+	// Collection to pair sessionId's and tokens (the inner Map pairs tokens and role associated)
 	private Map<String, Map<String, OpenViduRole>> mapSessionIdsTokens = new ConcurrentHashMap<>();
 
+	// URL where our OpenVidu server is listening
 	private String OPENVIDU_URL;
+	// Secret shared with our OpenVidu server
 	private String SECRET;
 
 	public SessionController(@Value("${openvidu.secret}") String secret, @Value("${openvidu.url}") String openviduUrl) {
@@ -45,51 +50,74 @@ public class SessionController {
 		}
 		System.out.println("Getting sessionId and token | {sessionName}={" + sessionName + "}");
 
+		// Role associated to this user
 		OpenViduRole role = LoginController.users.get(httpSession.getAttribute("loggedUser")).role;
+		
+		// Optional data to be passed to other users when this user connects to the video-call
+		// In this case, a JSON with the value we stored in the HttpSession object on login
 		String serverData = "{\"serverData\": \"" + httpSession.getAttribute("loggedUser") + "\"}";
+
+		// Build tokenOptions object with the serverData and the role
 		TokenOptions tokenOptions = new TokenOptions.Builder().data(serverData).role(role).build();
 
 		if (this.mapSessions.get(sessionName) != null) {
 			// Session already exists: return existing sessionId and a new token
 			System.out.println("Existing session " + sessionName);
 			try {
+			
+				// Get the existing sessionId from our collection with 
+				// the sessionName param ("TUTORIAL")
 				String sessionId = this.mapSessions.get(sessionName).getSessionId();
+				// Generate a new token with the recently created tokenOptions
 				String token = this.mapSessions.get(sessionName).generateToken(tokenOptions);
 
+				// Update our collection storing the new token
 				this.mapSessionIdsTokens.get(sessionId).put(token, role);
 
+				// Add all the needed attributes to the template
 				model.addAttribute("sessionId", sessionId);
 				model.addAttribute("token", token);
 				model.addAttribute("nickName", clientData);
 				model.addAttribute("userName", httpSession.getAttribute("loggedUser"));
 				model.addAttribute("sessionName", sessionName);
 
+				// Return session.html template
 				return "session";
+				
 			} catch (Exception e) {
+				// If error just return dashboard.html template
 				model.addAttribute("username", httpSession.getAttribute("loggedUser"));
 				return "dashboard";
 			}
-
 		} else {
-			// New session: return a new sessionId and token
+			// New session: return a new sessionId and a new token
 			System.out.println("New session " + sessionName);
 			try {
+			
+				// Create a new OpenVidu Session
 				Session session = this.openVidu.createSession();
+				// Get the sessionId
 				String sessionId = session.getSessionId();
+				// Generate a new token with the recently created tokenOptions
 				String token = session.generateToken(tokenOptions);
 
+				// Store the session and the token in our collections
 				this.mapSessions.put(sessionName, session);
 				this.mapSessionIdsTokens.put(sessionId, new ConcurrentHashMap<>());
 				this.mapSessionIdsTokens.get(sessionId).put(token, role);
 
+				// Add all the needed attributes to the template
 				model.addAttribute("sessionId", sessionId);
 				model.addAttribute("token", token);
 				model.addAttribute("nickName", clientData);
 				model.addAttribute("userName", httpSession.getAttribute("loggedUser"));
 				model.addAttribute("sessionName", sessionName);
 
+				// Return session.html template
 				return "session";
+				
 			} catch (Exception e) {
+				// If error just return dashboard.html template
 				model.addAttribute("username", httpSession.getAttribute("loggedUser"));
 				return "dashboard";
 			}
@@ -107,29 +135,33 @@ public class SessionController {
 		}
 		System.out.println("Removing user | sessioName=" + sessionName + ", token=" + token);
 
+		// If the session exists
 		if (this.mapSessions.get(sessionName) != null) {
 			String sessionId = this.mapSessions.get(sessionName).getSessionId();
 
 			if (this.mapSessionIdsTokens.containsKey(sessionId)) {
+				// If the token exists
 				if (this.mapSessionIdsTokens.get(sessionId).remove(token) != null) {
 					System.out.println(sessionName + ": " + this.mapSessionIdsTokens.get(sessionId).toString());
 					// User left the session
 					if (this.mapSessionIdsTokens.get(sessionId).isEmpty()) {
-						// Last user left the session
+						// Last user left: session must be removed
 						this.mapSessions.remove(sessionName);
 						System.out.println(sessionName + " empty!");
 					}
-					model.addAttribute("sessionId", sessionId);
 					return "redirect:/dashboard";
 				} else {
+					// The TOKEN wasn't valid
 					System.out.println("Problems in the app server: the TOKEN wasn't valid");
 					return "redirect:/dashboard";
 				}
 			} else {
+				// The SESSIONID wasn't valid
 				System.out.println("Problems in the app server: the SESSIONID wasn't valid");
 				return "redirect:/dashboard";
 			}
 		} else {
+			// The SESSION does not exist
 			System.out.println("Problems in the app server: the SESSION does not exist");
 			return "redirect:/dashboard";
 		}
diff --git a/openvidu-mvc-java/src/main/resources/templates/index.html b/openvidu-mvc-java/src/main/resources/templates/index.html
index ba94b58e..63e3ced1 100644
--- a/openvidu-mvc-java/src/main/resources/templates/index.html
+++ b/openvidu-mvc-java/src/main/resources/templates/index.html
@@ -44,10 +44,12 @@
 			<div id="img-div"><img src="images/openvidu_grey_bg_transp_cropped.png" /></div>
 			<form class="form-group jumbotron" action="/dashboard" method="post">
 				<p>
-					<label>User</label><input class="form-control" type="text" name="user" required="true"></input>
+					<label>User</label>
+					<input class="form-control" type="text" name="user" required="true"></input>
 				</p>
 				<p>
-					<label>Pass</label><input class="form-control" type="password" name="pass" required="true"></input>
+					<label>Pass</label>
+					<input class="form-control" type="password" name="pass" required="true"></input>
 				</p>
 				<p class="text-center">
 					<button class="btn btn-lg btn-info" type="submit">Log in</button>
diff --git a/openvidu-mvc-java/src/main/resources/templates/session.html b/openvidu-mvc-java/src/main/resources/templates/session.html
index 4c2097be..69f4b370 100644
--- a/openvidu-mvc-java/src/main/resources/templates/session.html
+++ b/openvidu-mvc-java/src/main/resources/templates/session.html
@@ -136,7 +136,7 @@
 					};
 					initMainVideo(event.element, userData);
 					appendUserData(event.element, userData);
-					$(event.element).prop('muted', true);
+					$(event.element).prop('muted', true); // Mute local video
 				});
 
 
diff --git a/openvidu-mvc-node/server.js b/openvidu-mvc-node/server.js
index 6ff69a31..3ebb44fe 100644
--- a/openvidu-mvc-node/server.js
+++ b/openvidu-mvc-node/server.js
@@ -60,15 +60,17 @@ var users = [{
     role: OpenViduRole.SUBSCRIBER
 }];
 
-// Environment variables
+// Environment variable: URL where our OpenVidu server is listening
 var OPENVIDU_URL = process.argv[2];
+// Environment variable: secret shared with our OpenVidu server
 var OPENVIDU_SECRET = process.argv[3];
 
-// OpenVidu object
+// OpenVidu object to ask openvidu-server for sessionId and token
 var OV = new OpenVidu(OPENVIDU_URL, OPENVIDU_SECRET);
 
-// Objects for storing active sessions and users
+// Collection to pair session names and OpenVidu Session objects
 var mapSessionNameSession = {};
+// Collection to pair sessionId's (identifiers of Session objects) and tokens
 var mapSessionIdTokens = {};
 
 /* CONFIGURATION */
@@ -100,28 +102,36 @@ app.get('/dashboard', dashboardController);
 
 function dashboardController(req, res) {
 
-    if (isLogged(req.session)) {
-        user = req.session.loggedUser;
-        res.render('dashboard.ejs', {
-            user: user
-        });
-    } else {
-        var user = req.body.user;
+	// Check if the user is already logged in
+	if (isLogged(req.session)) {
+		// User is already logged. Immediately return dashboard
+		user = req.session.loggedUser;
+		res.render('dashboard.ejs', {
+			user: user
+		});
+	} else {
+		// User wasn't logged and wants to
+		
+		// Retrieve params from POST body
+		var user = req.body.user;
         var pass = req.body.pass;
         console.log("Logging in | {user, pass}={" + user + ", " + pass + "}");
-
-        if (login(user, pass)) {
+		
+		if (login(user, pass)) { // Correct user-pass
+			// Validate session and return OK 
+            // Value stored in req.session allows us to identify the user in future requests
             console.log("'" + user + "' has logged in");
-            req.session.loggedUser = user;
-            res.render('dashboard.ejs', {
-                user: user
-            });
-        } else {
+	    	req.session.loggedUser = user;
+			res.render('dashboard.ejs', {
+				user: user
+			});
+		} else { // Wrong user-pass
+            // Invalidate session and return index template
             console.log("'" + user + "' invalid credentials");
-            req.session.destroy();
-            res.redirect('/');
-        }
-    }
+			req.session.destroy();
+			res.redirect('/');
+		}
+	}
 }
 
 app.post('/session', (req, res) => {
@@ -129,23 +139,43 @@ app.post('/session', (req, res) => {
         req.session.destroy();
         res.redirect('/');
     } else {
+       	// The nickname sent by the client
         var clientData = req.body.data;
+        // The video-call to connect ("TUTORIAL")
         var sessionName = req.body.sessionname;
+
+        // Role associated to this user
         var role = users.find(u => (u.user === req.session.loggedUser)).role;
+
+        // Optional data to be passed to other users when this user connects to the video-call
+        // In this case, a JSON with the value we stored in the req.session object on login
         var serverData = '{"serverData": "' + req.session.loggedUser + '"}';
+        
         console.log("Getting sessionId and token | {sessionName}={" + sessionName + "}");
 
+        // Build tokenOptions object with the serverData and the role
         var tokenOptions = new TokenOptions.Builder()
             .data(serverData)
             .role(role)
             .build();
 
         if (mapSessionNameSession[sessionName]) {
+            // Session already exists: return existing sessionId and a new token
             console.log('Existing session ' + sessionName);
+            
+            // Get the existing Session from the collection
             var mySession = mapSessionNameSession[sessionName];
+            
+            // Generate a new token asynchronously with the recently created tokenOptions
             mySession.generateToken(tokenOptions, function (token) {
+                
+                // Get the existing sessionId
                 var sessionId = mySession.getSessionId();
+                
+                // Store the new token in the collection of tokens
                 mapSessionIdTokens[sessionId].push(token);
+                
+                // Return session template with all the needed attributes
                 console.log('SESSIONID: ' + sessionId);
                 console.log('TOKEN: ' + token);
                 res.render('session.ejs', {
@@ -156,15 +186,27 @@ app.post('/session', (req, res) => {
                     sessionName: sessionName
                 });
             });
-        } else {
+        } else { // New session: return a new sessionId and a new token
             console.log('New session ' + sessionName);
-            var mySession = OV.createSession();
-            mySession.getSessionId(function (sessionId) {
-                mapSessionNameSession[sessionName] = mySession;
-                mapSessionIdTokens[sessionId] = [];
 
+            // Create a new OpenVidu Session
+            var mySession = OV.createSession();
+            
+            // Get the sessionId asynchronously
+            mySession.getSessionId(function (sessionId) {
+                
+                // Store the new Session in the collection of Sessions
+                mapSessionNameSession[sessionName] = mySession;
+                // Store a new empty array in the collection of tokens
+                mapSessionIdTokens[sessionId] = [];
+                
+                // Generate a new token asynchronously with the recently created tokenOptions
                 mySession.generateToken(tokenOptions, function (token) {
+                    
+                    // Store the new token in the collection of tokens
                     mapSessionIdTokens[sessionId].push(token);
+                    
+                    // Return session template with all the needed attributes
                     console.log('SESSIONID: ' + sessionId);
                     console.log('TOKEN: ' + token);
                     res.render('session.ejs', {
@@ -185,16 +227,21 @@ app.post('/leave-session', (req, res) => {
         req.session.destroy();
         res.render('index.ejs');
     } else {
+        // Retrieve params from POST body
         var sessionName = req.body.sessionname;
         var token = req.body.token;
         console.log('Removing user | {sessionName, token}={' + sessionName + ', ' + token + '}');
-
+        
+        // If the session exists
         var mySession = mapSessionNameSession[sessionName];
         if (mySession) {
             var tokens = mapSessionIdTokens[mySession.getSessionId()];
             if (tokens) {
                 var index = tokens.indexOf(token);
-                if (index !== -1) { // User left the session
+                
+                // If the token exists
+                if (index !== -1) {
+                    // Token removed!
                     tokens.splice(index, 1);
                     console.log(sessionName + ': ' + mapSessionIdTokens[mySession.getSessionId()].toString());
                 } else {
@@ -202,7 +249,8 @@ app.post('/leave-session', (req, res) => {
                     console.log(msg);
                     res.redirect('/dashboard');
                 }
-                if (mapSessionIdTokens[mySession.getSessionId()].length == 0) { // Last user left the session
+                if (mapSessionIdTokens[mySession.getSessionId()].length == 0) {
+                    // Last user left: session must be removed
                     console.log(sessionName + ' empty!');
                     delete mapSessionNameSession[sessionName];
                 }
diff --git a/openvidu-mvc-node/views/index.ejs b/openvidu-mvc-node/views/index.ejs
index 7f3bccbd..b4eb9629 100644
--- a/openvidu-mvc-node/views/index.ejs
+++ b/openvidu-mvc-node/views/index.ejs
@@ -44,10 +44,12 @@
 			<div id="img-div"><img src="images/openvidu_grey_bg_transp_cropped.png" /></div>
 			<form class="form-group jumbotron" action="/dashboard" method="post">
 				<p>
-					<label>User</label><input class="form-control" type="text" name="user" required="true"></input>
+					<label>User</label>
+					<input class="form-control" type="text" name="user" required="true"></input>
 				</p>
 				<p>
-					<label>Pass</label><input class="form-control" type="password" name="pass" required="true"></input>
+					<label>Pass</label>
+					<input class="form-control" type="password" name="pass" required="true"></input>
 				</p>
 				<p class="text-center">
 					<button class="btn btn-lg btn-info" type="submit">Log in</button>
diff --git a/openvidu-mvc-node/views/session.ejs b/openvidu-mvc-node/views/session.ejs
index 2da7c891..ca5212b3 100644
--- a/openvidu-mvc-node/views/session.ejs
+++ b/openvidu-mvc-node/views/session.ejs
@@ -92,7 +92,7 @@
 		// When the HTML video has been appended to DOM...
 		subscriber.on('videoElementCreated', function (event) {
 		
-			// Add a new HTML element for the user's name and nickname over its video
+			// Add a new HTML element for the user's name and nickname just below its video
 			appendUserData(event.element, subscriber.stream.connection);
 		});
 	});
@@ -106,6 +106,7 @@
 
 	// --- 3) Connect to the session passing the retrieved token and some more data from
 	//         the client (in this case a JSON with the nickname chosen by the user) ---
+
 	session.connect(token, '{"clientData": "' + nickName + '"}', function (error) {
 
 		// If the connection is successful, initialize a publisher and publish to the session
@@ -118,7 +119,7 @@
 			if (isPublisher()) {
 
 				// --- 4) Get your own camera stream ---
-
+				
 				var publisher = OV.initPublisher('video-container', {
 					audio: true,
 					video: true,
@@ -134,12 +135,12 @@
 					};
 					initMainVideo(event.element, userData);
 					appendUserData(event.element, userData);
-					$(event.element).prop('muted', true);
+					$(event.element).prop('muted', true); // Mute local video
 				});
 
 
 				// --- 5) Publish your stream ---
-
+				
 				session.publish(publisher);
 
 			} else {