How do you install a aftermarket radio in a 1991 Cadillac brougham?

To install an aftermarket radio in a 1991 Cadillac Brougham, start by disconnecting the negative battery terminal to ensure safety. Remove the dashboard panel by unscrewing any screws and gently prying it off. Disconnect the factory radio's wiring harness and antenna, then connect the aftermarket radio's harness using an adapter if necessary. Finally, secure the new radio in place, reattach the dashboard panel, and reconnect the battery.