How do I set a product's inventory?
Select Products from the left hand navigation panel. Click on the three stacked dots next to the product you’d like to set inventory for.
This will open the product editor. In the product editor, locate the Inventory section. If you would like to set your inventory to a specific quantity, enter the quantity you have in stock. If you offer unlimited inventory or fulfill orders as they come in with no limits, check the box next to Unlimited Inventory.
Once an item with a set inventory has sold out, it will display as "Sold Out" to customers.