Correctly positioning stirrup leathers on a saddle is vital, yet something many people are not confident enough to do properly. The first tip would be to perhaps practice using your saddle on a saddle stand. This way you can take all the time you need and make any mistakes before involving the horse, ensuring you can be well prepared when the time comes.
It’s best to start on the left hand side of the saddle, due to this being the mounting side and therefore of primary importance. Begin by lifting the saddle skirt so you have access to the stirrup bar. You should then take the stirrup leather, holding it with buckle facing you and creating a circle with your hand, and place the back of it at the end of the stirrup bar where you can then push it further on to the bar. Next you should pull down on the stirrup leather which should tighten the loop and then tuck the rest of the leather into the right side of the flap. This process should be repeated for both sides of the saddle.
It is recommended that the stirrup leathers should be used on top of the flaps, though sometimes they can be placed under, if for example you are trying to minimize wear and markings on the flaps, though this can lead to problems such as interference from buckle guards and girth billets. Most important is that you go back and check everything before beginning to ride to prevent an accident. Make sure the stirrup leathers are secure, the end of the bars are popped up to keep things in place, and also that the girth is buckled on firmly to the billet straps. Remember that there is no harm at all in being over cautious when it comes to properly positioning stirrup leathers.