openldap-ltb configuration

Hi
for some reason on Centos 7.9 , I have to install and configure openldap LTB not the standard openldap
First time for me
After installing the rpm, I would like to add a new database in addition to the existing ones

I modified the slapd.conf to change the rootdn & suffix for the mdb
and restart slapd-ltb service. But obviously it is not enough
Does anyone knows how to create and set a new database with openldap LTB ?

The command with the standard OPENLDAP : ldapadd -Y EXTERNAL -H ldapi://// -f <file> does not work

databasemdb
maxsize1073741824
suffix"dc=my-domain,dc=com"
rootdn"cn=Manager,dc=my-domain,dc=com"
# Cleartext passwords, especially for the rootdn, should
# be avoid. See slappasswd(8) and slapd.conf(5) for details.
# Use of strong authentication encouraged.
rootpwsecret
# The database directory MUST exist prior to running slapd AND
# should only be accessible by the slapd and slap tools.
# Mode 700 recommended.
directory/usr/local/openldap/var/openldap-data
# Indices to maintain
indexobjectClasseq

thanks