When importing a product, creating a new product, or editing a product there is the option to set levels for 'reorder point' and 'reorder amount'. You will need to do this for each outlet and variant.
The reorder point is the level stock must get to before Retail POS identifies this stock as 'low stock' and the item appears on your low stock report. It is also the level that must be reached in order for Retail POS to automatically populate an order with this item (if choosing 'autofill from reorder point' in the new order tab).
The reorder amount is the default amount that will be ordered when a product that hits its reorder point is added to an order.
Setting these up when creating or importing new products will allow you to automatically populate orders therefore saving time later.