How do you enter radio codes on 1992 Cadillac STS?

To enter the radio code on a 1992 Cadillac STS, first, turn on the vehicle's ignition. Then, press the "AM/FM" button to activate the radio. Use the preset buttons (usually numbered 1-6) to input the code by pressing the corresponding number for each digit in the code. Once the code is entered correctly, the radio should unlock and resume normal operation.