Once the Vendor has delivered the products to your Warehouse, open the Purchase Order again and click Receive.
After clicking Receive, select who is receiving the product. Click Save to finish.
After saving, a confirmation will be shown, along with the Receive Order.
The Inventory has now been updated by adding the products received.
An alternate way to update inventory quantities is to create skip the Purchase Order steps and create Receives directly.
To do so, go to Warehouse Menu, Products, New Received.
Select the Vendor, Received By, and Add the products with their corresponding quantities.
When done, click Save. You will receive a confirmation and a Receive Number. The Inventory is now updated with the added quantities.