Two privileges are managed in this package at differents levels, one is the privilige that a user has over dotlr-catalog package (admin, create, none), and the other one the privilege that the user has over one dotlrn-catalog course (admin,none). Depending of what privilege the users has, acces to some pages and the display of information will be different. For example if you you have admin or create privilege over dotlrn-catalog package then you can acces to every page under the "dotlrn-catalog/dt-catalog/" url, if you are admin all courses will be shown there but if you only have create privilege the only your courses will be show. When you create one course then the admin privilege will be granted to you over that course (item_id). There are two ways to grant permission to other users at the same two levels described before. The admin of dotlrn-catalog package can grant/revoke other users the create privilege over the package, and, any user can grant admin privilege over one of his courses to any other user in the system.