Transaction Rollback

Have two methods one insert data into table and sceond method update it base on another table. I want to use transaction to rollback the transaction if insert or updation fails. Used IDbConnection. Here is the code

        public int BulkImportSkipExportedCustomers()
        {
            int result = 0;
            try
            {
                using (IDbConnection conn = objDataConnection.dataConnection)
                {
                 
                    var param = new DynamicParameters();
                    param.Add("@amsexported", 0);
                    StringBuilder sb = new StringBuilder("insert into AMSLeadExportLog(EnteredDate,LeadId,SessionId,LeadStatus,PolicyNbr,LeadAuto) Select distinct GETDATE(),LeadId,SessionId,Status,PolicyNbr,Auto from LeadExportLog where AMSExported=@amsexported");
                   result = conn.Execute(sb.ToString(), param, null, null);
                }
            }
            catch (Exception)
            {
                throw;
            }
            return result;
        }

        public int UpdateSkipExportedCustomers()
        {
            int result = 0;
            try
            {
                using (IDbConnection conn = objDataConnection.dataConnection)
                {
                    var param = new DynamicParameters();
                    param.Add("@leadsamsexported", 0);
                    param.Add("@amsexported", 1);
                    StringBuilder sb = new StringBuilder("Update l set l.AMSExported=@amsexported,l.AMSExportDate=GETDATE() from LeadExportLog l where l.LeadID in(Select LeadID from AMSLeadExportLog) and l.AMSExported=@leadsamsexported");
                    result = conn.Execute(sb.ToString(), param, null, null);
                }
            }
            catch (Exception)
            {
                throw;
            }
            return result;
        }

If any one method gives error,entire transaction should fail. Suppose 10 records are inserted and updation fails then both methods must be rollback. please let me know how to do this