You should mount your horse on the left side, mounting a house is getting on the horse's back. To mount the horse place your left foot in the stirrup on the left side of the horse, pull yourself up and over the horse's back landing in the saddle. Quickly put your other foot through the other stirrup. To sit in a saddle you must be centered and balanced. You need to be able to lift your entire body up and stand in the stirrups. Make sure the stirrups are even. In the stirrup your foot needs to be steady and the balls of your feet need to be on the stirrup. If you have your feet too far in or out it could affect your balance on the horse. Make sure you always have your feet in the right place. To balance you need to keep your body straight,
