Xbox360 live, membership gold, how to hook up your first xbox360 online for live!?

Hello, thank you for your time. I was wondering I know people have told me that i can hook my INTERNET cable well the ethernet Cable from my computer straight to my xbox360, Well when i do this do i have to set some thing up on the computer, or do i pay for all this on the xbox360 its self, so say i go and get a membership live gold membership can i just Type all this stuff into the xbox360 or do i have to do it on the computer, it would make more since to do it on xbox360 witch i think im going to but im afraid if i don't ask i might run into some thing wrong, can some one please give me there experience on how they first had to hook there xbox360 to online, do i have to just register this stuff all on straight on the xbox360? My email is ryanheeter94@yahoo.com but please don't send me spam, please answer as manny questions as u can on here thanks!