Quick Version: Click on Manager, then Stock. Find the stock item you are looking for, double-click on the Barcode column and either scan in the barcode, or enter it as it appears on the product, then hit Save at the bottom of the screen.

Step-by-step guide

1. Click on Manager (1), then Stock (2).
   
   
   
2. Search for the stock item that needs to have the barcode updated.
   
   
   
3. Double-click on the Barcode field for the stock item.
   
   
   
4. Update the barcode by either scanning in the barcode with your handheld barcode scanner, or enter it as it appears on the product.
   
   
5. Hit Save at the bottom of the screen. The barcode has now been updated.