The fuel filter is on the inside of the drivers side frame rail about half way between the door. Hard to miss. If you don't know what it looks like to verify - take the new out of the box and you will know what it looks like.

Relieve the fuel pressure by unplugging the fuel pump and cranking the engine. You can unplug the pump by worming your hand through the drivers side rear wheel well to the top of the tank. if you have the metal fender shroud still on your truck, unbolt it for access. Once you have it unplugged, crank/start the engine until it dies (it may not start at all). Let it crank a few seconds more before replacing the filter. Just remember to plug everything back in when finished.