It is just held in place with the small clips and screws.
You can see it the Assembly Manual Sect 1, Sheet 18.00.
You can find the Assembly Manual on line if you don't have a hard copy - which was my bible when re-assembling my mine.


1951 Chevy 3100 5-Window
"Howard"
In the Stovebolt Gallery
More pix on Photobucket