There are two parts to managing your Stock for a competition. The first is to make stock available for the draw.  Tap the stock icon to view all the events that are set to Assign Stock in the event settings. Note: the number of Competitors for the Event is shown so you know how many animals will be required.

Tap an Event to begin assigning stock. Tap a Stock Contractor to view their available stock for this event. Tap on each animal to make it available for the stock draw. To assign an animal as re-ride stock, swipe the row from left to the right.

Tap Save and you will see the list of stock assigned to this event. Tap < Back to return to the list of events.  You will now see the number of animals as Stock Available and the number of animals assigned as Re-Ride. Continue with other events as needed until all have an appropriate amount of stock available.