All OES services require that you create User objects to represent the users on your system. The Linux User Management (LUM) and Samba components on OES also require that you create a LUM-enabled Group object that you can assign the users to.
In addition to these basic objects, it is usually helpful to organize your tree structure by using Organizational Unit objects to represent the structure of your organization and to serve as container objects to help manage the users, groups, servers, printers, and other organization resources you can manage through eDirectory.
The OES 11: Getting Started Guide provides introductory exercises for creating container objects as well as Group and User objects in eDirectory.
For detailed information on understanding, creating, and managing the various objects your organization might require, see the NetIQ eDirectory 8.8 SP8 Administration Guide.