To create custom types, you must belong to a role that has the "Manage Asset Types" permission. Besides allowing you to create custom types, this permission allows you to edit and delete any user-defined asset type. Additionally, it allows you to edit certain predefined types that are installed with CentraSite. By default, users in the CentraSite Administrator or Asset Type Administrator role have this permission, although an administrator can grant this permission to other roles.
For more information about permissions, see About Roles and Permissions in the document Users, Groups, Roles and Permissions.
