a/c compressor

I need to know is there specific instructions on how to remove and install a/c compressors. reason asking my backyard mechanic replaced mine in less than ten minutes and now my entire vehicle is dead and will not run. it was fine before compressor.anyone know what is going on with this.

Possible loose connector/ground wire?

look to see if the Knock sensor is unpluged and also the camshaft sensor. knowing what car or engine could help out more. Check fuses and senors in the area of the A/C compreesor for disconnected or broken wires.