Do you know how to "send" a horse over obstacles? it's leading, but you are leading from behind. YOu have the leadline (and I prefere to use a rope halter and a 12 foot heavy rope leadline) and you use the weight of the leadline to kind of "suggest" to the horse to move forward , past you . You can support this with a driving pressure from your hand, a whip or the tail end of the leadline. You send your horse ahead of you, over ground poles, or through a gate, around a barrel , between two obstacles , up onto anything "bridge" like.
You get good at sending your horse, having them stop , turn around and come back to you and sending them the other direction. This builds a connection in them in looking to you for direction. The more intersting and challenging things you can come up with for your horse to be sent through, the more the horse builds confidence in itself, too.
Trust , for you horse, means that you KNOW what you want to happen and have a very clear intention in your direction. Horses become easily upset and then have to "take over" if they are not sure that the human knows what is going to happen next. So, you have to stay one step ahead in your ground play. If you are going to send him over an obstacle, you must "know" that you only want him to go over, then stop and turn, not go over and then ?
Even if you aren't sure what to do or why, pick something, and go with it with conviction. Your horse won't know that you randomly selected that.