I start out by making them straight. I them shove one end into the door until it engages with the little retainer clip at the bottom, leaving the excess sticking straight up on the outside of the window opening.
I them begin the first bend at the upper rear corner of the window opening. Slow as you go, mashing the buckling as they appear with lineman pliers and wide blade screw driver.
Once that corner is done, I move on to next bend (or to mark it to be cut to length at the vent window).
You may not be using the right quantity of beer prior to this operation. That can be detrimental.
