Blowing out lines

Can someone who has done this post some details about how to do it? My husband and I can do pretty much everything for closing except we are unsure about this. Our builder told us it was always worth it to hire this out to be on the safe side so that it is done correctly. I paid someone 190.00 today for less than 30 minutes of work to do this and antifreeze the lines. I'm thinking "how hard can this be?" I have a vinyl liner 20 X 40 inground, with 2 skimmers, 3 return jets, a main drain, a sand filter, gas heater, inline chlorinator (which I never use), pump, and booster pump for a Legend cleaner. I know all the fittings to take out on the heater, pumps, and filter. We have a commercial grade air compressor. What we don't know is where to connect the air and in what order to blow things out, and how do you know when it is done? Then, where does the antifreeze go? The guy today used 2-5 gallon jugs. Thanks.