You go to the bar on the top and click on "My mibba "
and on the left hand side there will be this colem that says "Profile" or my profile, or something like that :P
and then you click on CSS than scroll down to the bottom of the page and it'll say "layouts" and you just click the blue thing that says "click here" and when you find the one you like click instal.
well...
like what do i like 2 do?