With the ruler you measure the size, in this case of the drawing on the cardboard box and take out strips for a base with the shape you want.
Dissolve some recycled anime in gasoline, this will create a mixture similar to varnish and paint the box, it will give it a shiny effect, this also works on wood.
Once dry, start to assemble your box of boxes.
Put details you want.
This is my participation in the DIYHub & Clean Planet Collaboration RECYCLING CONTEST. I hope you like it.