Agree with first post. But no your horse needs to know the basics of side passing, leg yields, bending, roll backs ect. Before it even sees the pattern. And you should walk the pattern for at the very least half a week before you even trot. And if he blows the turns at a trot, drop back down to a walk. You also want to bend them around the barrels, using your inside leg and rein. And move them out into a "pocket" going into the barrels, them come off as close as you can get, then point him straight at the next barrel and repeat. Plus it takes about 2 weeks of consistantly trotting the pattern before most horses are able to canter and even then you have to work with them to pick up the right leads going into each barrel.
That is my complete crash course, because its hard to explain it all through typing.
It's a long process like any other training for a dicipline. You would benifit by finding a trainer to help you. It would also save alot of time.