They just snap together, although there is an adapter ring that goes between the radio and the control head. It usually gets tossed when the radio is converted to remote head, though.
You can temporarily piece it back together to do the programming, if you need to.
As for the ribbon cable, there's a black dot on each end, that black dot needs to line up with the "0" on the circuit board end.
I agree, this sounds like it's having issues with the remote head set up, I've had it happen before. You can program the CDM series through the rear 20 pin connector, but building that cable might be harder than just putting the radio back together.