To make the marquee I first decided to orient my cardboard with the fluting running vertically since most of the letters to be cut from cardboard run in the same direction. I used one side of a box with the top and bottom flaps folded back to create a triangular base. Next, I gently scored the the edges of the area I wanted to display and then started to gently peel away the top layer of paper to reveal the corrugated part of the cardboard below.
I used a chopstick to pry up some of the paper from between the flutes of the cardboard. It really helped to move the process along. (I would definitely enlist the help of any willing young spectators for this part.) If you are lucky enough to find some cardboard with the corrugated part exposed, then you can just glue it on top of the marquee base and get to work peeling the backs off of all the cardboard letters or shapes that you are using.