We do have several good documents to review when learning about LDAP and reconfiguring Harvest to use it.
In the documentation, the Implementation Guide is your best source. You'll find bits and pieces on LDAP authentication all through this document but in particular you should review:
Chapter: Installing CA Harvest SCM on WindowsHow to Prepare for the OpenLDAP Installation
Chapter: Configure Broker and Server on UNIX, Linux, and zLinuxConfigure-Broker-and-Server-on-UNIX,-Linux,-and-zLinux
Section titled "External Authentication Configuration" (no hyperlink for this so you'll have to look for it.)
In the Knowledge Base there are several articles as well. Some of these might be a bit older but the concepts are all there. You should review:Authenticating Harvest users over LDAP is taking too long. How can we make LDAP authentication work more efficiently?Can I configure external authentication to use more than one LDAP server?Trouble while setting up Harvest LDAP authentication. Which tools could help?LDAP direct connection Trying to Setup an LDAP direct Connection
Finally, there is a special command line utility you can use to test your LDAP settings before adding them to your HServer.arg file:hauthtst Command-Authentication Server API Test