To activate an upgrade, please run the iLok License Manager app (from iLok.com), Log in to your iLok account. Note that if your iLok account have been created for you automatically when signing up for the Softube account, you will first need to do a password reset at iLok.com. In this case your iLok user id is the same as your Softube user id.
Find your new license by clicking the account top left, then right click the license and select activate. This will prompt you to complete the upgrade by surrendering the license(s) required for the upgrade. Note that all activations for that license needs to be available, that means either deactivated or on the machine where you are doing the surrender.