The larger filter is the located on the drivers side frame rail right under the cab. The cap is the same size as the oil filter cap is. There is a small plug on the side of the frame mounted filter assembly...I believe it is uses a 6mm allen wrench to remove. There is a replacement part that can be bought through International that you can remove by hand...make it MUCH easier to drain the water.
Anyway, pull the plug first and wait a while...let it drain so you don't get such a big bath. Then pull the cap.
The smaller fuel filter is located on top of the engine, very close to where the oil filter is.
Don't tighten them up too much...just like with the oil filter cap.