This is easy.
Locate the filter. It's on the passenger side. Has 6 T26 screws holding it in with a lip for a flat head screw driver. Unscrew the bolts (some say disconnect the lines but I've never had to do this on mine), use the screw driver to pry the lid off the canister.
Remove old filter, pour diesel fuel into housing. Remove the old O-ring at the top of the housing plate -- BE SURE that the new one is pre-lubed (drop it in the diesel) and that you have ensured it is on correctly. If not diesel will spray everywhere. That has happened to me before. Push the new cartridge onto the stalk on the housing plate, and put it back together.
It takes about 10 minutes.