Air Cond Question??

[karl]

I had a guy working on my 1990 vehicle at my house and he disconnected the hose going to the compressor for whatever reason? I heard a loud pop and saw steam rising. I asked what he did and he said he had to disconnect the hose because it was in the way. I dont want him working on my car any more so i will finish the job. The air was working great before this. Question: what do i have to do to get it working again? Just charge the system or is there more? Thanks