Although the box looks like it was easy to build, it wasn't! First a framework was constructed onto which the chipboards were attached. Then a back door was made, one which could be opened from the inside.
Probably the hardest part was making a hole for my tummy, I had to make several dummy models from cardboard until I got it just right. One also had to take into consideration that my tummy would be a bit bigger by the time of the art show opening.