Just a little tip when doing wiring for the first timers. Buy LOTS of plastic wire ties in various lengths. I use the 4 inch, 6 inch, and 7 inch mainly. You will want to put a wire tie about every 6 inches, and if you space them evenly they give a nice professional look to the finished job.
I also use the wire ties to temporarily hold the wires together while running various circuits. You can use them in the normal way, then cut them off as you move along, but that is wasteful and costly. If you turn the wire tie around and insert the end back in so that the smooth side is against the teeth of the wire tie it enables you to slide it back apart and reuse it. Hard to explain what I mean, but simply flip the wire tie 180 degrees and you will see what I am talking about.
Don
Oh, one other tip. Put a big garbage can next to the car and toss all the stuff you trim off in there as you go...........it sure saves a lot of mess, and doing a wiring job creates a lot of trash.