02 sport trac, pioneer deh-p960mp

I am going to be putting a new head unit in my 02 sport trac probably a pioneer deh-p960mp. The factory stereo has three wiring harness' coming off of it, I assume the two extra's are for factory amps?  How do I get a harness that will go into the three harness' and into the single input on the stereo?  I have a good basic knowledge of installation but I have never run into this before and I refuse to get hosed by having it installed by a shop. Thankswhat?,I cant hear you

ha ha ha ha. go get hosed its fun.  just kidding anyway only one harness does anything it should be the harness at the very bottom right of the back of the radio. one of the other plugs is for a cd changer and i think the other is for some factory steering wheel controls maybe. but yea its a pretty standard install and the kit and harness can be found in any custom shopthe best part of a job is seeing the bumper get smaller over the horizon