Aftermarket Radio won't work 04 Classic

Hey all, I just installed a Pioneer entry-level cd player in my '04 Malibu Classic.

This is the second or 3rd time I've put a CD Player in a car and I'm having an issue with it not working.

I double checked to make sure all the wires match up with each other regarding the harnesses. Those are all fine and I've got my ground mounted up ok.

I've been told I need to get an "interface unit" to get this thing to work. Could anyone point me in the right direction?

Thank you in advance for any input.

Does it even turn on ? Where did you connect the ground ?