Ok so I finally found a guy willing to lend me his sandblasting machine. Problem is that he has had it there for over a year without using it. Its a snap-on

cabinet and he has a huge ass compressor.
Now my questions are that I didnt notice a separate container where the media goes, what it has is a bag on top of the blasting cabinet where he said the media goes, is he right?
Also I was looking into getting a gun or different nozzles, any advice on which would be a good gun to buy. Also I see the machine is need of new gloves.
Ok so as far as that cabinet that holds the media I read that there are 2 types, I really didnt understand how this works. If anybody can provide me some info on what to buy it would be a huge help.
One last question, the best media to blast say for example aluminum wheels ( I think cast aluminum) is AO?