if you want to insert the data from the two tables (header and detail) to test table you can do something like this...

1. get the inserted value in dbo.inserted

2. join dbo.inserted and Header Table.

sample code below

CREATE TRIGGER Detail_Insert

ON detail

FOR INSERT

AS

insert into Detail_table

select I.id, * from dbo.inserted I

inner join header H

on I.id = H.Id

This code will work. Just make some neccessary adjustment as to what fields to you want