When you install a SharePoint Server Agent, a farm backup set is created automatically. This farm backup set can manage backup and restore operations for the client. If this is all you need to accomplish, you do not need to create or modify any backup sets.
You can also create a user-defined backup set to manage and back up a specific group of subclients.
For information about creating a user-defined backup set, see Creating a User-Defined Farm Backup Set.
For general information about backup sets, the different types, and how they fit within the logical structure of a CommCell Console, see Backup Sets Overview.