please be aware that teaching you everything would be a long chore. you have a browser for a reason! plus, anything else i don't teach you is probably on here. this is a very useful and in-depth page. you can learn about custom backgrounds and stuff. this page will teach you small things like buttons that take you places and what-not.
surround whatever you want in the "center" variable. easy huh??? you can also put "align="center" before ending a paragraph variable. it'd look like this:
i usually just put the first "center" in my header line before h1. then i put the end of it at the bottom of the page right above "/body" to make sure everything in the page is centered.
i use buttons for navigation. just go back and copy the code for my website button and paste it right above your header. then change the image link to "/images/yourbutton.png" or whatever image you use. you can use my button as a template for your own. when you have that done, upload the image to an "images" folder on your neocities dashboard. then change the link of your button to go to a new page of yours.
you should most definitely not use marquee for scrolling text but i have no idea how CSS text scrolling works so this is just a backup if you can't figure that out:
you can like add scroll delay and stuff but you gotta look that up yourself lol