When you run out of a certain product you will need to order in more..
To find the Purchase Orders section, please head to the administration area. Please click "Purchase Orders".
Once on the Purchase Orders page you can either check your Critical Stock Shortages or you can just order items.
Once you have sent the order to your supplier you must wait for that order to come in.Then, when the order has arrived you can "Receipt Goods".
That will then make the order change to "Received".