1999 Chevy Cavalier vacuum control disconnected

I took my vehicle in to get the air conditioner serviced. They checked it and filled it up with freon. They said it had no leaks, but the vacuum control was just laying down inside there and needed to be reconnected. They could not tell me how long it would take to reconnect it, because they would have to take off the front dash board to do it. Thus, they could not tell me how much it would cost. Is this something that I could do myself? Could you instruct me.

Thanks!!