Zach, Rigpig is right, the order is wrong. This one that I gave you is for 1/4" line. The direction those pieces are facing is correct so all you need to do is to have it as: Nut, small piece, tapered piece, valve. When you tighten it all up the nut pushes against the small piece which mashes it into the tapered piece and this makes the seal on the line, then the tapered part makes the seal with the valve fitting. You will be able to swap valves if needed in the future but the nut and ferrules will be permanent on the line. The other nuts are caps as stated and the center piece is just a union if you had to joint two long runs together. I would think you could get more ferrules at any place that sells compression fittings. I know there are a couple places on Columbia blvd in Portland and maybe Portland Oil Filter Service sells them too. If you are going there to get 3~AN stuff anyways you could give them a call and verify. Just tell them you need compression fitting parts for a swagelok ball valve. The model number is on the side of it if that helps.