Install it. Use it.

Just like any other program. Only difference is it's been modded to not ask you to verify that you paid for it. Or, if it came with other files that will modify the program post-install, there should be a readme included that tells you how to use those other files. However, each ware would uses different files, so there's no way in Hell for us to know the specific directions for some random, unknown program. Follow the tutorial on the site you got it from, Google, or guess. I'd say guess, 'cause I've never heard of a warez program that's hard to install.