90 lumina 4 door, cd wiring problem

Ok so i pulled out the radio, man is it ever big, and went to connect my cd player, but heres the problem, the power plug for the lumina has 5 wires, while my cd player, has 3, I need to know which wires i need to connect, i have tried number of times and can't get it to work. please help me,

just a guess, because I've never actually played with a 90-94 car, but the red (acc./battery/ignition power, 12V), the black (ground) and yellow (battery backup. for the clock/station presets/etc).

Just a guess.