My preference is a lead rope held in the asking hand, the one closest to the horse's hindquarters or a thin willow. Remove his halter then go stand in the middle and just wait to see what he wants to do. If he starts trotting just turn away from him so your shoulders aren't facing him. Let him trot around if that's what he wants to do. When he slows to a walk turn to face his withers and barely move the rope. Use your other hand to point the direction as you wiggle the rope. It is ok to play around with this. Try different things like stepping back, or stepping back and doing a half turn and see how he responds, or doesn't. You are learning another language and he'll forgive your mistakes because what you are doing shouldn't inflict pain. It will start to come along and one day it's like he's forgotten everything. That might be the time to challenge him a little with some obstacles. Just enjoy the process and each moment and don't worry about how quickly you both progress. You are both learning.