how to write data into existing excel template using c#

using System.Drawing;  
using Spire.Xls;  
  
namespace Create_Excel_File  
{  
    class Program  
    {  
        static void Main(string[] args)  
        {  
            //Initialize a new Workboook object  
            Workbook workbook = new Workbook();  
            //Get the first worksheet  
            Worksheet sheet = workbook.Worksheets[0];  
            //Write string values in a cell  
            sheet.Range["A3"].Text = "This Excel Document is Created by Spire.XLS for .NET";  
            //Save workbook to disk  
            workbook.SaveToFile("Sample.xls",ExcelVersion.Version97to2003);  
            try  
            {  
                System.Diagnostics.Process.Start(workbook.FileName);  
            }  
            catch { }  
        }  
    }  
}