The addressbook does not have a large list of configuration settings, but those that are there can be found in the Tools menu.
To add a new LDAP server to your available contact folders:
Select Tools->Addressbook Sources
Click Add.
Enter the server information.
The name that you see on the screen. This could be anything you wish.
Address of the server where the addressbook is located.
Select this if the server needs a password to access the addressbook.
The internet port to connect to in order to access the database. This is normally 389.
The base node to use for all your searches. Contact your administrator for information about setting this up.
How broad the search is in the directory.
Click OK.
Click OK to permanenty make changes or Apply to temporarily set the changes.