private void TablesAndCells( string file, int tableIndex )
    {
      using( var document = DocX.Load( file ) )
      {
        // Get the table to modify
        var table = document.Tables[ tableIndex ];

        // Add a new column at the end
        table.InsertColumn();

        // Add a new row at the end
        table.InsertRow();

        // Save the changes to the document
        document.Save();
      }
    }