how to generate Excel sheet

if (ds.Tables[0].Rows.Count > 0)
            {
                CreateExcelDoc exceldoc = new CreateExcelDoc();
                #region creates the main header

                exceldoc.createHeaders(2, 6, "NAME OF THE INST", "F1", "I1", 0, "", true, 15, "");
                exceldoc.createHeaders(3, 6, "LOCATION, LOCATION-521165,LOCATION District", "F2", "I2", 0, "", true, 10, "");

                
                   
                    exceldoc.addData(6, 6, ds.Tables[0].Rows[0]["1"].ToString(), "A" + 6 + "", "A" + 6 + "", "");
                    exceldoc.addData(6, 7, ds.Tables[0].Rows[0]["2"].ToString(), "A" + 6 + "", "A" + 6 + "", "");
                    exceldoc.addData(6, 8, ds.Tables[0].Rows[0]["3"].ToString(), "A" + 6 + "", "A" + 6 + "", "");
                    exceldoc.addData(6, 9, ds.Tables[0].Rows[0]["4"].ToString(), "A" + 6 + "", "A" + 6 + "", "");

                    exceldoc.addData(10, 6, "Name", "A" + 6 + "", "A" + 6 + "", "");
                    exceldoc.addData(10, 7, "Marks", "A" + 6 + "", "A" + 6 + "", "");
                    
                    if (ds.Tables[0].Rows.Count > 0)
                               {
                                    for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
                                   {
                                       exceldoc.addData(i + 11, 6, ds.Tables[0].Rows[i]["5"].ToString(), "A" + (i + 11), "A" + (i + 11), "");
                                       exceldoc.addData(i + 11, 7, ds.Tables[0].Rows[i]["6"].ToString(), "A" + (i + 11), "A" + (i + 11), "");
                                       

                                   }
                               }
              
                exceldoc.app.Visible = true;

                #endregion
            }