Move your code inside of the src folder. Once it’s there, it’ll be compiled on-the-fly every time it’s saved.
IntelliJ only recognizes files in specific locations as part of the project – namely, anything inside of a blue folder is specifically considered to be source code.
Also – while I can’t see all of your source code – be sure that it’s proper Java syntax, with a class declared the same as the file and that it has a main method (specifically public static void main(String[] args)). IntelliJ won’t run code without a main method (rather, it can’t – neither it nor Java would know where to start).