Checking off the [Limit inventory] checkbox, then enter the quantity. When a successful purchase happens, the value of the quantity automatically decreases and will be displayed on the quantity field. When the quantity reaches zero, the customer will be notified that the item is not available. To increase the quantity, simply enter a value on the quantity field.

You can also limit your daily inventory. This allows you to control your inventory for each day of the week. Check off the [Limit daily inventory] box to enable it.