From this screen, you can perform tasks on Roles (see Roles and Capabilities for details on Roles):
You can view and edit capabilities by clicking Capabilities next to the Role you wish to edit: see View Capabilities for Role
You can add a new Roles by clicking Add Role: see Adding a Role
You can edit a Role by clicking next to the role you want to edit: see Editing
a Role
You can manage membership of a role by clicking
next to the role you want to work with: see Members
You can delete a role by clicking