As a fellow newbie who's just done this...
There are good how-to instructions on kde-look.org, but a lot of the files and apps that people have uploaded are not necessarily set up to be newbie-friendly, some of the README instructions have just left me more confused. I've had many that I can't get to work for unknown reasons, and others that worked flawlessly. There has been a lot of folder shuffling and path tweaking to do in some cases.
There are plenty there that I've had first time success with though, fun stuff!
A lot of wonderful themes there, plus icons, wallpapers, sounds, everything to make your KDE ultra-cool!