You start from the rear and work towards the front.

Here are some poor photos of installed panels in a 54/55 Suburban. Earlier Advance-Design years would be the same, except at the windshield.

You might want to seal the upper-side (and edges) of each panel (piece of cardboard) - epoxy primer or maybe a varnish.

You can find out where each bow goes by "dry fitting" them. Each piece will fit in only one of the locations.