The fuel filter is very easy to install. Only two bolt holes to drill to mount it on a transom, bracket, or in my case, I bolted the filter onto the side of a old milk crate! (I use the milk crate to hold containers of bait, and a auto quick start battery that I use for my boat's electrical system)
As stated by Ron, there are four threaded openings in the fuel filter's metal top. One of inlet holes, and one of the outlet holes are to be plugged with the metal plugs included with the filter kit.
Unless your kit comes with two additional metal fittings that will go into the remaining inlet and outlet openings, you will need to go to a auto supply store and buy two fittings. Take one of the metal plugs with you to ensure that you get the proper size. I bought two 3/8" SAE x 3/8" spur brass fittings. The spur side is for the fuel line. The 3/8" SAE thread goes into the fuel filter openings.
The purpose of having four openings...two inlet and two outlets...is to make routing of your fuel line easier....which side of the filter do you want your fuel line from the tank going to???
I was advised that the fuel primer bulb should be installed between the fuel filter and the motor. That is what I did, and I am able to pull fuel from my fuel tank that is at the front of my boat. Motor runs great with the filter in place.
Hope this helps,