Hi Suzanne, I taught my horse by using his love for treats! I would hold a carrot between his forelegs, and every time I held it a little lower until he understood. After that I combined it with touching/pushing his belly with my hand, until he understood the aid completely without the carrot 😊 watch out your horse won't bend in the knees, this is bad for their joints and tendons.

Putting a treat between its legs and having it slowly bring its head down