I don't use it because in the beginning too many treats are used IMO.
Technically what you'd do is:
Take a hand full of treats (alot of them)....click the clicker, then give the horse a treat. And repeat over and over and over and over and over and over and over .......so on and so forth. Then you'll have the horse do something....like put his hoof on a bucket (as an example)...then you'd click and give him a treat. And repeat and repeat and repeat.
And do that until the horse associates the "click" as a treat...then remove the treat.
Personally, I think it's using way too many treats, but that's just me