[CentOS] using windbind to connect to AD

Hello,

After a couple of years using Samba as a DC I figured I would start working it the other way around. I'm using CentOS, the latest and tried to use the GUI manager. I am sort of confused as there are acutally 2 windows. I filled out both and supplied the name of the AD administrator. Do I just put the AD domain in there with .realm after it? (eg testdomain.com.realm)? I tried with and without

I then tried to login with an AD user, but used his username only (eg user1) but it didn't work.

I am assuming that with this type of authentication, I will be able to login with user's from the AD directory...

Has anyone worked with this setup before?

Thanks,

James