The “External user database integration via LDAP (ActiveDirectory)” chapter contains information only needed for local Cerebro installations (see: “Local (On-premises) Deployment”).
You can setup Cerebro to use external user account database through LDAP. At the present moment you can import users from ActiveDirectory, however it is possible to configure Cerebro to work with any LDAP server.
Users logged under ActiveDirectory accounts (works for Windows only) can access Cerebro account without entering password.
If your working environment does not support ActiveDirectory (i.e. any non-Windows environment), it is possible to set up logging in using your domain credentials anyway. Your e-mail address might be used as your login.