@ChefBill On the welcome screen. You need to log in and enter your serial number.

If your premium serial number is already listed in your user account at https://www.magix.com/int/support/my-service-center/ you don't need to enter it again. In this case it is enough to just log into your user account and wait some seconds, so that Music Maker can connect to Magix' servers and enable your premium settings.