chaseolds

I recentley purchased a factory Am Fm stereo for my 72 cutlass conv. But im having problems understanding how to hook it up. The radio itself has the large plug that plugs into the stereo unit and three wires yellow(power) blue constant i think and black ground. The stereo unit only has a blue wire where are the speaker wires at I see no signs of plugs or wires. I have even opened the unit up! HHHHEELLP!!!