Here, you can select which message boards included in the import package will be imported into the system. The following extra option can be adjusted:
•Import custom table data - if checked, custom table records (the actual data stored in the tables) included in the package will be imported together with the respective custom tables. If you are importing to an existing site, this option is disabled by default.
Detailed information about the built-in export/import functionality in Kentico CMS can be found in Developer's Guide -> Managing sites -> Export and import.