A resource is anything that can be scheduled using a calendar, such as a conference room, or a projector. There is a separate resource LDAP entry for each such item. Create the LDAP entry and its associated calendar using the appropriate tools:
For Schema version 2 - Use Delegated Administrator to create the resource LDAP entry, and the Calendar Server utility resource to create the calendar.
For Schema version 1 - Use the csresource create command which creates both the resource LDAP entry and the calendar.
It is not necessary to explicitly create resource calendars. With autoprovisioning enabled, the first time a resource is invited, the system will automatically create a resource calendar for it. This is the same behavior as for users and groups.