Show no emotion or impatience, and do not become aggressive; that will defeat the propose of building boldness and confidence in the horse.
The Balance Beam is a fantastic tool to teach horses to focus, not only on the crossing but on any task at hand.
Remember that in the horse’s mind, the less you move your feet, the more authority you have. Stay quiet, calm, and show no emotions.
You should master the low balance beam before you graduate to the elevated one.