Question cubase pro 10

I downloaded the full version cubase pro 10 from the steinberg assistent downloader software.
is I would like to buy only the serial number what can I do?
Do I have to buy only the USB dongle or the software? .
Thank you I await answers

Hi and welcome,

USB-eLicenser is alway included in a new Cubase Pro or Cubase Artist retail version. The USB-eLicenser is not included in updates/upgrades.

So you will buy the software (Activation Code) and USB-eLicenser will be included.