For normal arena traffic, horses going in opposite directions should pass left shoulder to left shoulder. Switch every 15 minutes.
Faster gaits take the outside track along the wall.
Slower gaits take an inside track, far enough from the wall to give the faster horses plenty of room to pass. Boarders who ride during lessons should stay out of the way of the training and do as they are told by the instructor. Get clearance from others in the arena before jumping and call your fences. Once a jumper starts a fence, others give right of way. Get clearance from other riders and communicate your intentions.