I believe this is in the admin user guide, but here is a quick run through of how we have it:
In Directory Integration under Customer Management on the Active Directory Tab:
AD Source Name = LDAP://DCNAME/dc=domain,dc=com
Search Root = LDAP://DCNAME/dc=domain,dc=com
For search root, if you have a separate OU other than users, you'll need to include it in the search root path.
For Active, click yes.
For Enable EUD access, click yes if you want EUD access available to users that are synched.
For AD Synchronization Interval, choose how often you want it to sync. If you have a lot of new users daily, you may want to choose every so often. We have it at 6 hours.
At the bottom, enter the username/password that has access to the AD database. You can try blank, and if that doesn't work, enter something that has the proper credentials.
I believe that's it for the configuration. If you are using Windows authentication, ensure your EUD is setup for it. I may have missed a step or 2, so hopefully someone from GWI will chime in if I did.