Open the project in netbeans and navigate to the Main class of the project i.e., WebSocketChatApplication.java

Now, click on the 'Run' menu of top navigation bar and select 'Clean and Build Project'

Now, the Project will search for errors and rectifies them. In the same flow, the maven will look for the required dependencies in the project and downloads them for us, if required.

Now, select the Main Class 'WebSocketChatApplication.java' and right click on whitespace and click run.

Check the console/terminal below for the Status. It will show project 'BUILD SUCCESS' and the 'Server started at localhost 6369'. Please Stop TomCat Server, if you already have one installed and running in your system. This will override my custom server port 6369.

Now, open a browser and type 'localhost:6369' and the webpage will look like this. please refer to the image below.