anyone know how to hook up a stereo?

Hey guys, the sound forum is DEAD and I really need this question answered. I bought a cheap cd/mp3 player. I need it to work with my stock system. I dont have an amp and only need the 2 rear speakers to work because those are the only ones there im gonna try to hook up the dash speakers cause those should still be there. But anyways, i was told beacuse I dont have the stock amp I will need to splice the new harnes to the new cd player. I think i pretty much have everything figured out, and then I went and looked at my console,

Heres a pic, what are all these harneses for?? I only need the speaker harnes and the power harness. And i looked at the speaker wire colors and I think the left rear speaker hooks up to harnes #2 but idk where the other speaker wire is. Any help? Thanks alot guys.






heres the back of the cd player