The single pool of enterprise resources in P6 represents all people who will be working on projects. This is not the same as a Functional Organization Chart or payroll list, as the resources represent only the people assigned to work on projects.
Loading a schedule with resources and/or roles provides a number of benefits, such as:
Potential head counts over time so that the project is properly staffed and funded
Better coordination between the Human Resources department and the project group, based on valid forecasts that support the Project Staffing Plan
Physical space or through-put overloads can be more easily forecast and proactively addressed
Earned value can be more accurately measured according to industry standards
Identification of many risks associated with limited resources/roles, such as vacations, hunting season, and weather impacts
You can view resources by clicking on the 
icon, or by choosing Enterprise | Resources from the main menu.