I am not sure to understand what you would like to do exactly.
There are more information concerning LDAP in our Documentation. Two main elements:
LDAP synchronizer (available in subscription pack): it is a service for synchronizing Bonita BPM and LDAP directory users and groups in a single direction, LDAP to Bonita BPM. More info here: http://documentation.bonitasoft.com/ldap-synchronizer-2
LDAP connector that will search in a LDAP directory and returns a list. More info here: http://documentation.bonitasoft.com/ldap-connector
Hope this helps.