MERCI has it's own import feature to create MERCI enabled content types and basic items. More advanced imports require Node Import or Feed API/Feed Element Mapper/CSV Parser.
To use MERCI's basic import, first copy the merci_import.php, content_types.csv, and items.csv found in the Import directory to the root level of your Drupal install. Then open http://<YOUR-SITE>/merci_import.php in a browser.