When adjusting telescopic sights, the rear sights or dials are adjusted by a certain number of minutes-of-angle or “clicks” in a certain direction. Read the sight’s instruction manual to see how much each click changes the sight.
The rear sight is moved in the same direction you want your shot to move on the target. Moving shots from side to side is “adjusting for windage.” Moving shots up or down is “adjusting for elevation.”
Specific instructions about trajectory and what fractions or inches you should be above the bull’s-eye at various distances are usually included on sight-in targets. You also might consult a ballistics chart or get help from an experienced shooter.