The plant is a very important part of the vault. Get this wrong and it will not just result in a poor vault but could cause painful injury. The following plant drills work on plant technique a step at a time.
The pole moves through, right arm up the line of the body into an extended take of position. Looking for the right arm to do the movement, nice and swift, the left arm to act as a pivot for the pole to drop over. Don't take the weight of the pole with the Left arm.