Set your bookable resources at Settings → Resources. Each cage, bullpen or turf area gets a name, type and capacity. Players book a slot from the schedule; a booking can also pair a coach and (for private lessons) a specific player, so the front desk sees "Cage 2 + Coach Ramirez + Marco 4:30-5:00" in one row.
For team practices and birthday parties, create the class type once and it holds the resource for the full block. Cage rentals default to 30 min / 1 hour slots and can be walk-in or pre-booked.