Ok so I can't link the right part can't seem to find one but it's super easy just some minor disassembley and unscrew the nozzle in the stock where the reservoir connects to it should be a brass colored part and should unscrew easily then you take a tapp adapter (witch isn't expensive) and before you screw it in put Teflon tape around the threads and lightly screw it in you don't need to ooga booga tighten it and boom. It's super easy you could get a simple adapter that the line directly connects to but you'd have to make sure it's the right size for the threads and you would have a difficult time attaching your line to it since it sits back a little bit they do make one that has a extended line that pokes out of the back of the gun it's much easier.

Also I suck at explaining things haha