Firewall insulation, where do these pieces go?

[Quiny]

Any idea where these go? Also why does the black backing face forward for the firewall but the left and right sides have the insulation forward?

 

[Ronbo73]

If I remember correctly when I installed mine, the larger ones are glued to the backside of the kick panels and the smaller ones tuck into the upper door hinge bolt locations.
I think the black side gets the glue/adhesive because its more solid than the yellow, fiber insulation side.