I know I need to upload them all to my server
use the file manager, or even better, and ftp client, there is a list of them in the Computer Discussions forum.
how do I insert my own content
use an html editor or notepad, if you have M$ Office, then you have frontpage or expression web, which are pretty much the easiest to use, otherwise, you can google for "free html editor"
create multiple pages
use the page you got from the template, (probably called index.html or index.htm) edit it, and rename it to the name you want.
The free templates include a css file, and html index file and thatâ€™s it.
because thats all you need.
btw, if you want to change the color of anything, you change the css file, not the html file.