What do I do after creating my full basic website in VS Code Editor?

So, I'm really confused on what to do after I've built my basic website in VS Code Editor. I'm wanting to create user login, etc, so I learned I need to know Javascript, but does VS Code allow Javadcript code in the editor? I thought I read you can install extensions, but I'm not sure how that works exactly. Also, after I'm done adding all my code, what do I need to do next? I read I need a database or server or something, I'm just so lost as to what to do after my website is built what I do from there. I know I need mysql which I think is a server?

Anyway, I'm really wanting to make this horse simulated website. It's been a dream for a long time.

Thanks for the help in advance.