i just picked up the final piece i need to have a complete ro di unit. but i do not know how to link the 3 canisters together!! i know how to install it in the house like tapping into the cold water and tapping into the drain, and the instructions do not show how to link the unit together.. here is a pic . the 2 bottom canisters have 1 in port and 1 out port each, but the ro canister has 3 ports and they are not marked. plus there are 2 diferant filters for the bottom canisters and i dont know where they go .. one is a plastic looking filter and the other is a cotton looking filter.