There are two ways you can register devices with BRMS. You can use the Initialize BRM (INZBRM) command to perform the registration and initialization tasks for you automatically. Or you can perform these tasks yourself using other BRMS commands.
Whenever you add a device, be it manually or through the INZBRM command, you must create new media classes to match. BRMS only creates media classes for you during the installation process. For information about how to create media classes, see Setting Up Your Media Management Operation.