The arrows on most scopes point in the direction the bullet point of impact (POI) will be moved. So, if your bullet is hitting low, you turn the adjustment knob in the direction marked "UP". To move POI left, go in the direction marked "L" or opposite of the direction marked "R" depending on how your scope is marked. As mentioned above, move it the number of increments needed to give you the right amount of POI movement.