Generating a Sequential Number from SQL SERVER

Question

I'm making a sequence number form Certificate of Insurance booklet given to the agents so that the CI numbers can be tracked. My code is attached below:

CREATE PROCEDURE [dbo].[CI_SEQUENTIAL_Number]
    (
        @StartingNumber int,
        @EndingNumber int,
        @Header int
    )
AS

DECLARE @start int
DECLARE @end int

SELECT @start = @StartingNumber, @end = @EndingNumber

    WHILE @start <= @end
        begin

        INSERT INTO dbo.tblSeriesDetails

                (SeriesNumbers)

        VALUES(@start)

        SET @start = @start + 1

        where SeriesHeader_Id = @Header  error in this area.

    END

 without the where clause, it is running but when I insert the where clause i got an error "

Msg 156, Level 15, State 1, Procedure SEQUENTIAL, Line 25

Incorrect syntax near the keyword 'where'." Still newbie and still acquiring knowledge in sql server. Thanks for any help.