Importing submissions from Excel/CSV files into Ninja Form Submissions may require some coding wizardry, but you're on the right track.

You can add this functionality via custom code - consider checking out Ninja Forms' API documentation or exploring WordPress hooks to create a custom solution that meets your needs.

First, use a library like PHPExcel or fgetcsv to read and parse the Excel/CSV file. Then, loop through the data and programmatically add new submissions using Ninja Forms' API functions. Utilize the ninja_forms_insert_submission() function and provide the required form data and field values. Make sure to handle any validation or formatting required for the fields.

Once the loop completes, you will have successfully imported the submission into Ninja Forms. Don’t hesitate to join an online coding community or forum for guidance and support.