I've never actually done it...but the basic process is to park on a flat, level surface and turn the adjustment screws until the bubble in the built-in gauge reads level. It may also be helpful to do this parked in front of a garage or building with the lights on so you can see where the beams are pointing.
i just did mine a few days ago. park in front of something that isnt well lit. aim headlights. drive around and if you like placement on the road your done. if not then aim higher or lower. repeat for fogs. i didnt measure or use tape.