Previously, we've added the ability to add inventory via the SKU page (see: Adding Inventory by SKU.) Now you can add inventory to a PO by SKU from the PO page.
To start, click the '+Add Inventory' button then choose 'Basic Form'.
In this section, start typing the SKU you want the inventory items for and then fill out the rest of the fields (quantity, cost, status).
If you want to specify the ESNs instead of just a quantity, you can click on 'Set ESNs'.
As you type, SKU options from your product catalog will show.
If you don't have the SKU in your catalog yet, you can add it now.