Print a shipping label, entering the weight and dimensions for the first box.
Then go back to your orders page and use the option to purchase another label, entering the weight and dimensions for the second box.
If you don't purchase labels through eBay then you would purchase the shipping elsewhere and upload the tracking number, then go back to the order and click edit next to the tracking number so you can add the second tracking number.
You're allowed up to 5 tracking numbers per transaction.
