This diagram shows what the ports connect to. To use the one with the switch looking thing just push in the black ring around it(a standard quick release fitting) and pull out the plug(switch looking thing). Also, an easy way to reduce the tubing size(the vacuum system uses smaller tubing than the rest of the pnuematics) is to put a standard size quick release on the input side of a regulator and a smaller quick release(for the vacuum size tubing) in the output side since you should take the pressure down to 26psi for best performance anyway.
