The first step in creating a community involves specifying which users will be members. By default, a community is configured to include all users from the authentication realm to which it is assigned. However, you can configure a community to permit access to only a subset of users or user groups in a realm.
This is useful, for example, if you want to segment a realm into one community for employees and another community for business partners. You can then provide each community with the appropriate access agents or impose End Point Control restrictions if users are logging in from non-secure computers. Communities can also be referenced in access control rules to permit or deny access to your resources.
To assign members to an existing community
From the main navigation menu, click Realms.
Within the realm, click the link for the community you want to configure.
The Configure Community page displays with the Members tab displayed.