Rewiring Radio, som help needed please

Hello,
I had a radio stolen from a 91 Explorer and I'm having some issues with installing and wiring the new radio. The wire(s) that go to the speakers are not present where the radio is. All I have by the radio arr a group of 8 wires...maybe 20 guage or so. The wires that go to the speakers are a good 16 guage. I don't have a clue as to what the heck is going on here. Could someone please inform me about Ford's wiring, colors, etc?
Thanks in advance,
Dr. Edison

http://www.the12volt.com/installbay/detail.asp?info=alarm&year=1990-91&make=Ford&model=Explorer&ID=17794&type=Stereo


there is a site that should have the wiring info for you