headunit doesnt play music through speakers in my seville

[Randy Craver]

I have a 94 seville and I am trying to install an aftermarket headunit, all of the wires are connected. It turns on and shows that the cd is playing, but no music comes out of the speakers. Also I have to keep the yellow and red wires connected to each other to keep it turned on. The wiring harness I bought was a pain just trying to figure out how it plugs into the factory's, it seem like its not even for the car. My on screen display that tells you the tempature and everything, doesnt come up anymore because when I got out of the car and put the headunit to the side to run in my house to get something wires must have touched and it doesnt show anything now.
Do you have any idea why I cant hear music and why the osd went out.