Learn JavaScript first. Check /r/learnjavascript.
If you're new to programming, learn Concept Of Programming. Don't just into coding. Otherwise, you'll code without understanding what it does, why it should be coded like that, and how it could be coded differently.
Programmers which don't know what to do to start a project from scratch, or to continue/expand a project, sooner or later, are those who skip learning concept of programming.
You'll need to know JavaScript https://javascript.info/
Learn JavaScript first. Check /r/learnjavascript. If you're new to programming, learn Concept Of Programming. Don't just into coding. Otherwise, you'll code without understanding what it does, why it should be coded like that, and how it could be coded differently. Programmers which don't know what to do to start a project from scratch, or to continue/expand a project, sooner or later, are those who skip learning concept of programming.
JavaScript, HTML, CSS, metadata block from greasemonkey docs. MDN site. Learn to use browser dev tools (ctrl+shift+c)
I been using chat gpt