What kind of More infos? Do you mean a collapsible or dropdown text that reveals more content?

Anyways, MDN and W3Schools provide the finest tutorials and reference out there on the web, I recommend checking these out and acquainting yourself to the basics first. Backgrounds are pretty easy, color palettes are easy enough to generate and make, or if you mean gradients, that's also related to backgrounds. You can take a look at the source code of other users' userpages, just make sure to ask first if you want to copy them, or better, ask them for guidance.

Regarding autoplaying media...that's a big no-no for any kind of platform, especially inside user-generated content

Autoplaying media actually isn't allowed, according to Kirkburn if I remember right from a thread regarding the topic.

"We do not allow autoplay music on Fandom. Thanks!" - Kirkburn

The post is linked on Help:Audio, too.

^i did it on the grace wiki and never got in trouble, like half the other community did it too so idk what happened there

Well, you shouldn't. It's not nice to take the liberty of the user to choose whether they want to play or pause the piece of media on their own

What iif i just have it NOT autoplay

That's fine, and is what you're supposed to do with audio anyway.

Yeah i know. Take the autoplay off of it.