How to Configure Secure LDAP

I am trying to configure Secure LDAP connection from my ZAB to AD server. I have network connectivity between ZAB and AD server. . I got internal certificate and not sure how to update it in ZAB. ZAB is build on free bsd and it doesn’t have path [/etc/ssl/certs] to update Root and Intermediate certificate. Some forum suggest to install package ca_root_nss. I don’t find any document in Zscaler porta. did any configured Secure LDAP connection ?

Note:we are not using ZAB as authentication proxy. ZAB is just to sync AD with Zscaler cloud