Hold the tuner with your left hand while plucking the lowest string. Use the tuner to determine if the string is in tune. The tuner tells you whether the pitch is too high or too low. The lowest string on a concert harp is C. If you have a folk harp or a Celtic harp, the lowest string varies depending on the manufacturer.
Place the tuning key around the tuning peg located at the top of the instrument. If the pitch is sharp, tighten the tuning pin by turning the peg to the right. If the pitch is flat, loosen the tuning pin by turning it to the left.
Tune each string from C up to the highest pitch.