make my own hack?

how do i make my own hack, and if its a program i have to use, what is the download link?

You can program it with C++, VB, or any other language. If you'd like you can easily find some trainer makers.

ok, and how do i hack warrock so i have diifernt guns? (the shotgun, the chaingun, the invinsible rocket launcher.. ext)

... That you have to learn by reading tutorials and what not.

There are many different types of hacks you can make, the most common ones as of now are Cheat Engine hacks. As Dave said, there are several tutorials around here, just look around and see what you can come up with.