Go to Admin> Config
Set up the following.
Use LDAP Integration to display user details: (tick) otherwise the LDAP items wont appear on the System Summary page.
LDAP Base DN: (dc=mydomain,dc=com or similar depends on your Active Directory Domain)
This is important, as without this set correctly, you wont look in the correct AD container(s) for your user and computer accounts. This must be the container that contains the subcontainers with Computer and User containers... (err what?!)
LDAP Connection Server: ( the fqdn of an AD domain controller, myserver.mydomain.com for example)
LDAP Connection User: ( a user that can see the domain, try mydomain\administrator for example)
LDAP Connection Secret: (the above user's password)
Since you get a blank page, chances are its the credentials that are the problem. If you were connecting you would get a Not found in dc=mydomain,dc=local page.