Upon installing the Firmware Uploader and completing the update (if available), you will have the option for the license upgrade before closing the application.

Please select license on the confirmation page:

On the next screen you will enter the license voucher (ABCDEF-ABCDEF-ABCD) received via email and then select NEXT:

 

You will then receive an email with the license code to enter onto the next screen and complete the upgrade process.