Windows 8 Dual Boot installation

Hey,

So I recently bought a new laptop which runs Windows 8, and although I like some features of this OS, I would like to be able to run linux as well (I don't know much about linux but I think this is called a dual boot?).

I downloaded the torrent but I want to make sure that I set it up correctly so that I can choose between linux and windows 8, and so that I don't lose any files on windows. Any advice of how to do this would be greatly appreciated.

Also, I assume that linux won't run (and take up ram/CPU) while I'm running windows?

Sorry if these seem like naive questions, but obviously I'm new here

Thanks,
Steve