Only buttons aren't working are the radio buttons on the panel how can I fix?

I forgot to mention dome light not working either above head not the 2 lights by wind shield but one right in the middle above right shoulder. Also cd player plays on separate unit that car came with but no sound. Still think it could be the unit broke?

Sounds like you have multiple separate issues, unfortunately.

Fixed the dome light, lights on radio buttons I'm going to take the dash control panel apart and see about getting buttons fixed. I noticed the factory cassette player never comes on might be broke or no power running to it might have to get another. Would you know where factory amp will be on 2001 prius? I put my head to the floor to look under the seat I don't see one is it hidden in the seat or in the floor panel anywhere? Where else could it be?