Fill in the form at the bottom of the page with the fields as defined below and click Add:
Issue Type: The issue type. This can be a specific issue type or an "All unassigned issue types" which is used by default for all issue types which does not have mapping explicitly configured for it.
Mapping: The mapping to use with the issue type, as configured in the Mapping configurations (see Configure Mappings).
You will be taken back to the Mapping Scheme Configuration interface and the new issue type-to-mapping configuration will be in the list.