It is quite easy.
My horses are taught to face up (come when called) and to stand still (don’t need to be tied, then touching all over.
They must walk before I walk. They must halt before I halt.
So a click and they walk forward. Say Halt and they halt. A thumb on their chest and the word back and they back. Always 2 signals for back.
So without the halter you click and they walk forward, you say halt and they halt. For back they also learn that the word back and a tug of the tail means to step off a float and the word back and waving my finger side to side means back.
So if I am on horse back and want to go through a gate and a horse is on the other side of the gate, I can say back and wave my finger, they step back from the gate and I can open and go through it on my horse.
To catch, I call the horse. I usually do put on a halter but I don’t need to. I walk to the next gate and say halt. I open the gate. I click. The horse walks through the gate. I close the gate. Step to the horses shoulder, click and they walk beside me to the house, where they then stand to be groomed and tacked without being tied.