I just purchased a 92' Cadillac STS and there was no radio, so I went and bought an aftermarket radio for the car. When I went to install it, I noticed there are wires everywhere! I bought a test light and none of the wires seem to be hot. So anyways, the question I'm trying to ask is, I just want to run all new wires but I mainly need help knowing where the best place to run the hot (red wire) and where to run the constant (yellow) wires. Should I run straight to the battery? Where would constant power come from? Maybe a fuse? Any helpwould be greatly appreciated, thanks.

been covered
the radio is not in the dash merely the control unit
the tuner box is in the trunk