Why not try auditing a single Windows computer first?
https://community.opmantek.com/display/OA/How+to+audit+a+single+Windows+computer
Try using Open-AudIT to discover a subnet.
https://community.opmantek.com/display/OA/How+To+-+Use+Open-AudIT+Discovery+on+a+Subnet
Or use Open-AudIT to discover your entire Active Directory Domain.
How to use Open-AudIT Discovery on an Active Directory Domain