I'm having problems trying to figure out how CO2 canisters work. I've never actually used them before so how would you connect a CO2 canister to a piece of piping. What I have trouble understanding is how you would open the CO2 cartridge and connect it to the pipe. Would it be by puncturing the canister after the connection has been made (somehow) or do you open the canister beforehand and then quickly insert it to the pipe? Also I how much psi would there be if I had an 8g or 12g CO2 canister? I know it depends on the volume of the container, but whenever I try to look at the specifications of the item, I can't find pressure. Thanks!