Help with a door seal for a 4106

[nc4106]

I just purchased a new door seal which came in 4 pieces.  I can easily identify 3 of the door frame pieces.  I can not figure out where the fourth one goes, I assume it attaches to the door somehow.  The seal is L shaped and about 25' long.  I can't find help in the manuals.  Does anyone have any pictures, diagrams or direct knowledge of how and where to attach this seal?

[roadrunnertex]

The L shaped seal is for the bottom of the entrance door.  JLV