Setting up a Re-Order/or Re-Stock level allows for the system to do just that.  When an inventory level for a certain product reaches a certain level, it will create a purchase order for you in order to ensure that the inventory is replenished when you need it.  

How to set a Re-Order/Re-Stock Level

To be able to set a re-order/re-stock first, we go to our "Catalog">> "Products". To ensure that you can add a Re-Order/Re-Stock level to any product you are looking at, Click on the "+" icon which is located next to the Store name. This will allow you to see all of the Simple Variants of your products. Afterward, please proceed to edit an item. In the edit item screen, click on the Inventory tab to get to where we need to be, as shown below.

Here you will see a list of your stores.  In order to set a re-order/re-stock quantity for each simple variant you are editing, it is required that you double click on the desired item in a store that you want to set it for first before clicking the Set Re-Order Qty button. After ensuring a store is selected, click the Set Re-Order Qty button and you will be shown a screen as depicted below.

Here you can fill in the stock level in which you want the re-order to take place and the amount of the item you want to replenish.

After setting the re-order level, in order to make a Purchase Order for items that have reached your re-order threshold, please proceed to making a new Purchase Order by navigating "Inventory" >> " Purchase Order" >> Click on "New Purchase Order" . From here, after you select a store and Vendor you can navigate to the Action Menu >> Automation and hit "Autofill By Re-order levels" as shown below.

Once you have clicked on the Autofill By Reorder LEvels button a  pop-up window will appear, this will bring up the above menu and from there it will add any items from that supplier that need to be reordered.

After making the required changes, Hit save and you have completed the process!