If it is a P/N entering your inventory master list, you need first to input the part number and description and save the changes.
If the part is already in your inventory master list, look up the part by entering the number into the search box. Next, move to the Warehouse tab and click the "New Item" button.
The new warehouse entry will be placed under a generic PO marked with the number 1 and placed "In Stock" under the inventory Bird View. The origin will default to "Inventory".