A/C Cooling

I have a 87' Comanche that when I turn the air conditioning on the compressor doesn't kick on this truck has been sitting for some time now and just had a motor rebuild on it but I know nothing about ac systems.

Well it could be pretty much anything related to the a/c system. The first thing I would check is to see if you can energize the a/c clutch while its not running and if it will engage. I would also check for continuity on the pressure switch on top if the filter/dryer that sits under the compressor on my cherokee. You could just have no refrigerant in the system but you need to rule out some easy things first.