Horizontal aim is done by adjusting the screw on the outer side of the headlamp assembly. Vertical aim is done by adjusting the screw in the top center of the assembly.
Park the car 25 feet from a wall, make sure the vehicle is on a level surface, tires are properly inflated, and car is at its normal weight.
The horizontal center line of the low beam lights should be 25.4 inches off the ground. The vertical centerline should be 664 inches from the centerline of the car, and 1328 inches from the other headlamp.