Adding initial LDAP servers to ODSM can only be done from the command line.
Note: In the recent releases this can now be done in the Web GUI.
Run the OUD dsconfig utility.
choose option 6
Add both option (first option 1, then option 2)
once done
select options
8 1 5 5 choose 2 - new routes and add a route
Now the LDAP service will show in the WEB UI.
Then, from the web gui enable LDAP & LDAPS for the new server(s).