Posting trot is a basic riding skill that involves rising and sitting in rhythm with the horse's movements. To post trot, start by sitting deeply in the saddle and then rise slightly when the horse's outside front leg goes forward. As the horse's diagonal pair of legs hit the ground, sit back down. Keep your hands steady and maintain balance throughout. Practice the posting trot on a well-trained and calm horse, gradually increasing your speed and getting comfortable with the motion.