Here's what I found over at the Magpul site:
"The front uses a standard square front sight post, which can be adjusted with a 4-prong M16 sight adjustment tool. For each 1/4 rotation, the POI is moved approximately 1-7/8" at 100 meters, based on a 14.5" M4 sight radius."
"TheRear MBUS - The rear MBUS has a windage adjustment knob on the right side that adjusts the POI approximately 3/4" at 100 meters for each click. Both large and small apertures are provided; the small aperture flips forward out of the way, rather than rearward, and can be left down when stowing the sight."
To move the point of impact up, you rotate the front sight post clockwise. Down would obviously be counterclockwise.
Most people like a 50 /200 yard zero on their AR-15's in 5.56 cal.. The above adjustments will yield about half the distance of bullet impact movement indicated at 50 yards.