Instruct: Classify a given Amazon review as either positive or negative.
Query: No installation instructions!

I just bought one of these but have no idea how to install it. There are 4 NPT ports on this thing, and the only "installation" instructions (on the inside of the box) are about how to replace the filter after you have it installed! Does anybody know where to connect the 4 ports? As far as I'm concerned there ought to be an in-port and an out-port, I don't know what to do with the other 2! And I've searched the Internet, can't find installation instructions for this product anywhere! Help!