Enable Windows AD authentication on WACS

I have entered all the required information in the Windows AD authentication and now I want to change the default setting in from enterprise to AD. I found how to do this with IIS and TomCat but could not find anything for WACS. Could some one help me with this please?

Also once I saved the changes in CMC, I entered the AD credentials and tried to login to the CMC, but got the following error:

Account Information Not Recognized: Active Directory Authentication failed to log you on. Please contact your system administrator to make sure you are a member of a valid mapped group and try again. If you are not a member of the default domain, enter your user name as UserName@DNS_DomainName, and then try again. (FWM 00006)