Prism Users Guide - Chapter 2. Basics
2.4 Permissions - Basics

Permissions control employee access to specific program features and areas. 
Prism includes a default set of employee groups with permission appropriate for the group. You can modify the default groups and/or create your own groups and assign the needed permissions.
You can also assign "override" permissions. If a user does not have ALLOW permission for a task but does have OVERRIDE, an override prompt is displayed. This enables a manager (or other user with the ALLOW permission) to log in so the user can complete the task. 
For More Information
See the Chapter 27. Employee Groups for more information.