100+ W3C errors on my pages!

[Peegee]

I only know how to include css files. How would I go about doing this? Would I put it as a function? What sort of file am I going to have to make? and etc etc etc

:(

edit:

[link href="styles/PG_styles.html" rel="styles" type="text/html" />
[link href="css/PG_fonts.css" rel="stylesheet" type="text/css" />

[script language="javascript" type="text/javascript" >
validateCookies();
[/script>

^ doesn't do anything :(

edit: I check the page anyway and it is now valid xhtml 1.0 transitional but non functional. XD one more step and I'll be one of the happiest wackos in EoFF :D