As the book says. For adjusting the light sideways (horizontal), look under the right side (facing forward from the seat) of the bottom of the head light assembly next to the right fork. You will see the adjuster as described. Use a flash light. Easy to get at. Vertical, as described, you must first remove the windshield. On the left side (facing forward) on the low beam side, the adjuster is there a few inches down. If your vertical adjustment is out, where is your rear shock pre-load? If set too light for your weight, the rear of the bike will sag making the vertical adjustment too high.