If anyone can give me some css tips

Hi swaggy ppl! I'm doing my best with learning css but there's some things that are just not working and its hard to search up so it'd be greatly appreciated if someone could help out thanks!

These are some things i'm currently stuck on:

-How do i replace the "myspace.windows93.net" text at the top? I've figured out how to hide and add new text but I can't figure out how to hide and replace this part without hiding the mailbox and logout buttons too

-Replacing text in general- when i replace the "add to friends" and "message" buttons the new text is placed all weird idk how to fix the placement

Bonus things:

-I'm gonna try to learn some animation stuff to see if I can make the diff parts slide in when clicking on my page or make the song text move but any tips are appreciated!

-How to have a fixed image that overlaps the page and stays fixed in its position? idk how to describe it but lets say I wanted a giant floating eyeball to sit on the bottom left of my page...how would i do that?
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..i know these are a lot of questions pls spare me i only started learning this like 2 days ago i have 0 experience in coding ahhhh
Thank you to anyone who decides to help..you're a lifesaver i luv u<333
and if not, i still luv u too<333
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