Before I try to explain how I shaped this, there are some things we need to go over first.
There are only a few things you can do to a piece of sheet metal, Shrink it, Stretch it or bend it and roll it.
Shrinking and stretching Is actually shaping the panel. Bending and rolling is forming the metal.
I shrink and stretch the panel, so that it will fit the pattern. I bend, twist or roll the panel to put the panel into it's proper arrangement.
Different people do it different ways, I can only explain how I do it.
I need two things to shape a panel, I need a pattern to record the shape(flexible shape pattern) I also need a set of contour gauges or a buck, so I can put the panel into its proper arrangement.
I will discuss how to shrink and stretch later but there is nothing more important than understanding the difference between shape and form.
I fit the the panel to the pattern before I do anything,that is shaping. It might not look like what I am trying to reproduce but if it fits the pattern it will go into it's proper arrangement. You do that with your contour gauges. After you have the the panel fitting the pattern your next move will be to put it into arragment. You take your contour gauges out and bend, roll or twist the metal until they fit the contour gauges.
If you can get the shape right, it will go into arrangement and then it will fit perfectly every time.