If yours is 2001 4.4 than it should look just like mine, 2003.
Air filter is located right behind the passenger side (right side for US cars) front head light assembly. It's inside the black plastic semi-square box about 10x10" with four shiny metal clips. Undo the clips, lift the cover, remove old filter, clean out filter housing with vacuum clean if filthy, install new filter, replace cover, fasten the 4 clips. Done.
You might have to loosen the air mass sensor tube to gain clearance for the filter remove/replace. Just unscrew/loosen the clamp. When you see it, it should be intuitive.
Go here:
Xoutpost.com - Xoutpost.com x5tips.htm
Lots of How To's.