Here's how I do it, start with a full tank of fuel to make the L/P job easier, bleed the filter housing down with the lever, place a pan under the truck to catch all the fuel, spin the cap off and pull the old filter and put the new filter in place as well as the new O ring, tighten it down , close the fuel drain and bump the key so you have a 25 second run on the L/P, repeat the key bump 2 more times and then it should go, I watch my fp gauge at the vp and when pressure is there than its good to go, check for leaks and have fun.
cheers, Kevin