DSE Root/first entry

["Polidar, Volker" <Volker.Polidar@telekom.de>]

Dear friends,

I have installed the openLDAP 2.12 . Now I want to build an DIT for my Project, like this:

Root DSE
       !
       !------ DE
       !          !
       !          !---- company
       !          ...
       !
       !------ US
       !          !
       !          !---- company
       !          ...
       !------ GB
       !          !
       !          !---- company
       !          ...
      ....

But I don't know how to configure the Root DSE in the slapd.conf file.
In the slapd.conf file I have set the parameter suffix: suffix ""
My test.ldif file looks like this:
dn: 
ogSupportedProfile: 1.2.826.0.1050.11.1.1
SupportedLDAPVersion: 3
SupportedLDAPVersion: 2
subSchemaSubentry: cn=LDAPGlobalSchemaSubentry
objectClass: ldapRootDSE
objectClass: subEntry
objectClass: top
namingContexts: 
cn: ldapRoot

dn: c=DE
objectClass: country
objectClass: top
c=DE

dn: o=company, c=DE
objectClass: organization
objectClass: top
o: Danet
dtagOrgeOZ: 9806

dn: cn=Manager, o=company, c=DE
cn: Manager
sn: Manager
objectClass: person
...
Error Code: entry 1 has no dn
The entrys are in the id2entry.dbb, but they have no index. 

Is there any posibility to built a DIT with the first entry Root DSE?
How have I to set the parameters in the slapd.conf and ldap.conf files?
Any pointers or help is welcome.

Thank You!
Volker Polidar, Darmstadt