Make sure to select an employee and click on Actions > Inventory Count
(Sample of per item)
Key in the units in stock and click on OK to finalize.
If there is a mismatch on your inventory count, it will be shown on this Inventory count mismatch box. You have an option to recount it by updating the units in stock and clicking on resubmit this count or by clicking on continue anyway, that will update your inventory to what you have counted.
(Sample of bulk count or Per Category)