There are 2 trains of thought.
Ask what you want and when the horse is doing what you want. Stay quiet as a reward.
With this method I went from being 3rd in everything to winning every event I entered from One Day Events, Dressage, Showjumping and Jumping Equitation as well as my club’s gymkhana on my mongrel, completely conformationally incorrect, bought sight unseen for $100, who was only used when they had a extra man to round up cattle, who I thought was the most beautiful horse in the World, gelding.
I became a Level I instructor working for my Level II under a Level III Dressage Instructor riding Grand Prix.
I had never ridden trained horses before. I thought I had trained my last horse with my seat. I was having and giving dressage and jumping lessons in the mornings and taking out the 5 hour trail rides a day.
I could not ask a trained horse to do a trot to canter transition. Walk canter fine. Trot canter not the first time I asked.
I was told my hands are dead, my legs are dead and I was not using my seat.
They taught me to keep communication with the horse, when you stop you are abandoning the horse in the wind. My riding increased vastly with this method and I did learn to use my seat correctly, eventually, thanks to my Vinnie Girl, would was the complete opposite and price to Pepper.