How to set up web project (backend/frontend/database)

This is my first time developing a dynamic web application. I have worked with html/css/js before, and I am also a java developer.

My web application should have html/css/js in the frontend part and I want to use java in the backend part.

The thing is I don't have a clue how to set up a project like that and hours of googling didn't get me further.

I would appreciate any clue on how to get my project set up.