We have to define what kind of data we want to store in our LDAP directory. These definitions are stored in "schema files". In /etc/openldap/slapd.conf we see a section what schema files are loaded:
include /etc/openldap/schema/core.schema include /etc/openldap/schema/cosine.schema include /etc/openldap/schema/inetorgperson.schema include /etc/openldap/schema/rfc2307bis.schema include /etc/openldap/schema/yast.schema
This set of schemas can be uesd to add the user data we want to. Go on and have a look into the files. You may have more or less scema files. Basically we need the first 3 schema files. If you have more, you don't have to change your config at the moment.