An active directory source is configured in Administration > Control Panel > Authentication Sources.
Under Administration > Control Panel > Access Control the expected active directory users or groups do not show under the "User Accounts" tab or the "User Groups" tab.
Aria Operations 8.18.0
Users are not imported from source.
Under either "User Accounts" tab or "User Groups" tab in Administration > Control Panel > Access Control:
Within a few minutes the group should show up in the "User Groups" tab, and the users in that group should show up in the "User Accounts" tab.
Now roles can be associated with the desired users or groups.