I agree with the above posts 100%. High-level dressage maneuvers are not tricks, but the culmination of years of training through the training scale. I suspect that the reason that the instructions that you've found sound so simple is because they assume a high level of training on the horse already and are omitting the assumed years of mental and physical training from the directions.
My advice to you would be to look into finding a good dressage instructor/trainer, and see where your horse does stand, and start taking things up from there. There is so much that goes into high level maneuvers, not only the training background of the horse, but his conformation and physical strength play crucial roles in the ability to perform things like piaffe and passage.
Looking professional is far more about the quality of the training than the quantity of "tricks" taught.