When you create an authentication realm in AMC, a default community associated with the realm is also automatically created. This single community may be sufficient if you have a homogenous group of users whose resource needs and access methods are identical.
To configure a single community
Create a realm on the User Access > Realms > Configure Realm > General page that references an external authentication server. AMC automatically creates a default community that is referenced by the realm.
The default community settings are global and apply to any realms that reference it.
Configure the community by selecting the users or groups who belong to it, the access methods they’ll use to connect to the VPN, and optionally any End Point Control options.
If you have a diverse group of remote users, you’ll probably want to create multiple communities.