Red Giant subscription licensing will be managed via the Maxon App. When you launch the Maxon App for the first time, you’ll need to sign in with your MyMaxon account (or you can use your Apple, Google or Facebook credentials to sign in).
For products compatible with Red Giant Application, from within the Maxon App from the menu in the upper right corner, there will be an “Import Serials” option to add your serial number. Just copy/paste. Products prior to that will continue to be licensed from within the installer.
To use your product on a different computer, you may need to deactivate existing computers via the Maxon App or MyMaxon Customer portal.