Start out by bore sighting it if it's a bolt. Then procede to the range and start at 25 yards and get it shooting center of the bulls eye. Then to 50 yards, fir a couple of shots to make sure that it is still close to the bull. Then to 100 yards to fine tune. Sight it in at 100 yards with the scope set on the highest power. It doesn't happen too often any more but if the scope changes zero from lowest power to highest power it will minimise this if you sight it in on the highest power.