Changing the factory head unit

Considering this should be such an easy job, I'm having my fair share of trouble with it! How do you take the original head unit out?

stereo or a/c ???? 2 headunits bro, im assuming you mean stereo ....

Assuming you mean stereo unit:

Unscrew and remove the console cover that goes over the shifter (have to remove the center console with the compartment behind it first). Then you have four screws around the head unit holding it in. Pull, and disconnect the wiring harness and you're done.