Step 1. Gather relevant Credentials:
Target Client Configuration#UserCredentialsRequirements
Step 2. Discovery one device ensuring Credentials are working and good information is populating properly:
How to discover a single Device
Step 3. Decide how you want to run your discoveries(Computer, Script, Subnet):
How to use Open-AudIT Discovery on a Subnet
How to audit a subnet using a script
How to use Active Directory Discovery