Keith,
There are a number of write ups on the web. Procedure I use is as follows;
This works on cars, PUs, RVs, etc.
1. Park vehicle so headlights are 25 ft from wall or garage door on level surface.
2. Be sure RV is level and at ride height.
3. Locate center of headlight bulb (low beam if multiple bulbs). Measure distance from bulb to ground.
4. Place mark on wall at this height.
5. Check bulb on other side of RV front. Should be at same height. Place corresponding mark on wall.
6. Determine horizontal position of headlight bulb center on wall. You can use a side wall or edge of drive way as reference. Then measure distance from this reference point to center of bulb.
7. Mark this point on wall at bulb height previously found. Place X at this point.
8. Measure horizontal distance between bulbs on RV. Measure same distance on wall from X and place another X on wall at this point.
9, You now should have the locations of your headlights marked on the wall 25 ft in front of the RV.
10 Turn on you low beams.
11. Adjust the headlights so the center of the brightest point is slightly below and just to the right of the mark on the wall. I usually set it for about 1-2" max. This keeps the lights out of on coming driver's eyes.
12. Check you high beams. They should shine above the marks but horizontal position should be same as low beams.
Steve