It is on the inside of the driver's side frame rail. For/aft location is almost inline with the rear part of the driver's door. Crawl underneath the truck there, and you will see a small metal canister a little smaller than a soda can. This is the fuel filter. It will have a stainless line on each end of it.
Remove the lines from the fuel filter. Expect some fuel leakage. Pull rear line out of the way and slide the filter out, then slide the new on in the holder (you do not need to remove the holder from the frame, just simply slide the filter out). Notice that there is an arrow on the new filter indicating flow of fuel through the filter, the arrow should point toward the front of the truck.
I don't know the size wrenches you will need off of the top of my head, but you will need to different sizes (one to loosen the fuel lines, and one to hold the filter to keep it from turning).
Filter is Fram #3727.