public class CSVImportOptions : ImportOptions 

var workbook = Workbook.Create( "test.xlsx" );

var worksheet = workbook.Worksheets[ 0 ];

// Define a path to a csv document, the import options(which separator to use) and call the ImportData function.

  var stringSCVData = "Book1.csv";
  var stringCSVImportOptions = new CSVImportOptions() { DestinationTopLeftAddress = "C5", Separator = "," };
  worksheet.ImportData( stringSCVData, stringCSVImportOptions );

workbook.Save();