I'm a little confused. Do you want to do tricks on a horse like in the videos, or do you want your horse to do tricks like laying down and bowing? Can't help you with the former since I can't even do a cartwheel lol, but I have taught my horse to bow among other things.
Training horses to do tricks just requires common sense and a good grasp of how horses think. What I did to teach my gelding to bow was first to get him to follow my hand down between his front legs with a treat without moving backward. Obviously, praise and reward when they get it right, and just say "no" and try again if they get it wrong. Never get frusturated or angry at any attempt to comply. Anyway, then I pick up one front leg (usually whichever the horse "chooses" themselves) and guide the leg back while asking them to follow your hand and treat with their head. Verbally say "bow" as you do this...eventually you will just need to say the word without any other cues. They will eventually start to crouch further to the ground. You can then ask them to stretch out a little before picking up the leg, which will enable them to go down on one knee. My gelding grasped the concept extremely quickly and now positions himself to get ready to bow before I even ask. My mare on the other hand, just proved too clumsy to go all the way down, so she just does a modified bow instead ;) Be safe, and only do what you and your horse are comfortable with. You can use the same incremental principles to train other tricks too...this is just one example. I like trick training with many horses because it is a fun way to spend time with your horse without riding and can strengthen your bond. I would not suggest trick training with excessively aggressive or nippy horses because hand feeding treats often aggravates the situation.