openVPN ldap auth Active directory

Hello,
i plan to use ipfire/openVPN with LDAP auth. (Active directory).
but there is not much info around.
i found only
https://wiki.ipfire.org/configuration/services/openvpn/extensions/auth/ldap
and
https://forum.ipfire.org/viewtopic.php?t=9800&start=15
(use basic_ldap_auth from squid)

Any idea what i should do?