Rebo have put together a complete kit with everything you need to add a woodchip safety area under swing sets and other play equipment.
Included in the kit are wooden perimeter boards to contain the woodchip, weed control membrane to prevent weeds growing through the woodchip over time and enough woodchip to cover the area in an appropriate layer of wood chip as well as all fixtures and fittings needed to install the kit
Remember that play equipment should be erected 2m from any other structures or obstacles to allow a safe area to move around the play equipment without the risk of injury.