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

  {

    // Get the first worksheet. A workbook contains at least 1 worksheet.

    var worksheet_A = workbook.Worksheets[ 0 ];



    // Fill cells in 1st worksheet.

    worksheet_A.Cells[ "D5" ].Value = "This is the first Worksheet.";



    // Add a worksheet with default "SheetX" name.

    var worksheet_B = workbook.Worksheets.Add();



    // Fill cells in 2nd worksheet.

    worksheet_B.Cells[ "D5" ].Value = "This is the second Worksheet.";



    // Add a worksheet with name "Third Sheet".

    var worksheet_C = workbook.Worksheets.Add( "Third Sheet" );



    // Fill cells in 3rd worksheet.

    worksheet_C.Cells[ "D5" ].Value = "This is the third Worksheet.";



    // Move the third worksheet at index 0 (to be first).

    // The Move function takes worksheet ids, names or instances.

    workbook.Worksheets.Move( worksheet_C.Name, 0 );



    // Save workbook to disk.

    workbook.Save();

  }