Where's this stereo plug go?

I have a 95 GT with the factory cassette player. I bought an Ford CD player that came with a wiring harness to install below the stereo. Below are some pictures of the problem. There appears to be one harness connector that doesn't plug into anything, and the CD player has no power (won't turn on). The third pic shows another small (2 prong) plug-receptacle on the radio that has nothing going to it. Am I missing something? Any help would be appreciated. Thanks.

2 connectors that plug into radio:
View attachment 286073

Back of radio, connectors above plug into:
View attachment 286075

Lone connector that doesn't plug into anything:
View attachment 286077

...and again:
View attachment 286079
 
I'm pretty sure those CD players were controlled by the head unit. I know that square plug goes down to the Premium Sound amp. And the long one is probably power source wires and such. The other open terminal on the CD player is probably a link wire to the head unit.