I would like to offer you some advice with as much respect,concern,and thoughtfulness as I can without giving you the feeling that I am talking down to you.
This is a very common problem that occurs with young horses and getting them going is not too hard at all.
The goal is to get forward movement and have the young horse confident to carry the rider.
The balance of the horse and ride are key.
The rider is trying to instill a work ethic and a solid set of cues for the gait that they want.
It all comes down to creating impulsion!
I have said this several times before and I may say it a thousand time more.
The job of the handler is to "Inspire" the horse.
The very definition of the word means to influence by example.
What better example than a second horse that can provide the pace for the young horse.
The young horse learns and "Mirrors"
the lead horse.
It is totally natural for a young horse to lock on to an older and more seasoned one and look for guidance.
Impulsion is created without force and the idea of movement while carrying a load is learned.
A second rider is there for safety and to help set the speed.
Just a few rides like this a you will find that you have a different horse.
Do not overlook the use of a second horse to pony the young horse also.
This is done in the race horse world and is common in polo also.
It is used with horses being trained for trail and ranch work too.
What is not to like?
Here is a first ride using this method.