You can use the Import/Export feature in your Web Control Panel at https://net.brosix.com. The import process is explained in details in the Web Control Panel.
Here are details how to export user accounts from an Active Directory
https://help.brosix.com//export-active-directory-users-into-a-csv-file/
You can also use Brosix LDAP Sync Tool to automatically sync your Active Directory with your Brosix IM network.
Web Control Panel is available only in Brosix Enterprise.