Above and Foal good ideas. But first you have to get him/her used to an English bit. A loose ring or fixed ring jointed snaffle to start with - very kind in a horse's mouth. Then as Foal suggests, and above. YOU WILL HAVE TO LEARN TO USE THE LEG, WHOLE BODY TO SEND SIGNALS TO YOUR HORSE. (sorry, accidently used cap lock). But above all, you and your horse are relearning, be patient with your horse, and yourself!