I just finished installing the same thing. If you take your time, it's not that hard. Every wire is numbered, and the directions tell you where to connect each wire. You will probably also need a wiring diagram for your truck. You can find one in your shop manual, or by itself on e-bay for a few bucks.

The hardest part is making sure you have a good path to ground at each device. Grounding wires are not included with the harness. In some cases I made my own.