The stock reorder report shows all variants that match or have fallen below the reorder point, as well as variants with negative stock. This makes the reorder report a great tool for managing your stock as well as your backorders.
To use the Inventory Stock on Hand Report:
Go to the Intelligence section of your account via the main menu. Click on Inventory > Reorder Report:

Select the location from which you wish the stock information to be retrieved from via Add Filter > Location:
Click on Apply Filter to update the report. You can also select following metrics via Show Me menu to control what is displayed on your report:

Once you have entered the quantity of the all the required products, click on Reorder at the bottom of the page. You'll see the following confirmation message once the reorder has been processed:
And you are done!
You can continue reordering more products, or start working on the Purchase Order.