An imaginary line down the center of the barrel's bore is called the line of departure (LOD). Likewise, what you see in the center of the sights is called the line of sight (LOS). Sight adjustment is simply the angle between these two lines. This angle is traditionally measured in minutes-of-angle (MOA), but can be measured in any of the following units:
IPHM (Inch Per Hundred Meters)
You can select the sight adjustment unit you want from the Options menu and Sight adjust unit sub menu..
Usually, the sights are set so the bullet goes above the line of sight 10 to 30 yards from the muzzle and falls back below the line of sight 50 to 500 yards down range. The zeroed range is where the bullet falls back to the line of sight.