When in the Products section in the Dashboard, you can click the "Actions ⋮" button to access the purchase orders section. Once on this page, you will be able to see your previous purchase orders and track their status.
You can also create new purchase orders by clicking on the "+ Create new order" button. This will prompt you with a section where you can select the supplier you are creating the purchase order for, and other details such as the purchase order ID, some notes, a phone number, as well as the products and the number of units for each that you've ordered.
Once all this is complete, you can select "Create" to add the purchase order to your list for future tracking.