1997 Galant ES Radio/CD problem

I just bought a 1997 Mitsubishi Galant ES. It came with a Pioneer 12-CD loader in the trunk. It has Mitsubishi Radio/Cassette. For now, the radio does not pick up any station. Also the CD button does not connect to the Pioneer CD loader. I can see from the Pioneer remote that the CD loader is working fine. How do I get the radio to work well and also interface the CD loader to the Radio/Cassette. Any diagrams?
Thanks.

Now this Pioneer set-up is stock? If not, I have a similar set-up that runs through the antenna, and to use the radio all that you have to do is use the remote to turn off the CD player. (It's probably something different than what you are talking about though).