two radio plug types

I have a 2000 ford explorer with one radio wiring plug,red,with 15 wires.All the radios from other 2000 explorers in the yards have two plugs,so I bought a radio and need to know what each of the wires in the radio are for and how to wire them to the 15 wire plug in the dash.I already looked on the web for 2 hours,no info.I know what the wires are for in the dash,just dont know what the 23 wires in the radio plugs are for.Would you email me at wgreenbay56@yahoo.com ,thankspacecarguy56

is the 2nd plug a square one?If I'm to loud, then you're too old!!!

yes a smaller one,I just used the rectangle one and the radio works good,so what is the small one for? thankspacecarguy56