Confirmation of SQL Transaction

Hi,

I have the code below where I am trying to use an sql transaction.
I would just like confirmation that I have got it right or whether the transaction should actually wrap up the whole procedure!

Thanks

BEGIN


      -- SET NOCOUNT ON added to prevent extra result sets from
      -- interfering with SELECT statements.
      SET NOCOUNT ON;

     DECLARE @numOccs As  Integer
        SELECT @numOccs = Count(emailAddress)
          From tbl_EmailAddresses
         Where emailAddress = @emailAddress
         
        If isnull(@numOccs, 0) > 0
        BEGIN
          SET @ReturnValue =  '0'
        END
        ELSE
            BEGIN
            BEGIN TRAN TM
                  BEGIN TRY
                        COMMIT TRAN TM
                              INSERT INTO tbl_EmailAddresses
                              (emailAddress)
                              VALUES (@emailAddress)
                              SET @ReturnValue = '1'
                              END TRY
                              BEGIN CATCH
                  ROLLBACK TRAN TM
                  SET @ReturnValue = 'error' ;
                  END CATCH
            End
END