Assemble the crates upside down, with three on each side one atop the other making sure they fasten together well underneath to make two towers.
Measure from the side facing outward of the first stack to the outside of the second tower to be sure your wood planks are the right size to fit over top.
Place 2 to 3 wood planks or boards overlapping the crates on the top and position them so you can safely place heavy equipment on top of the boards.
Now cover the stand over the entire surface with your black sheet so that it won't allow light through. Many people place lights underneath for added special effects while DJ-ing.
Now you can put your equipment over top and Voila! You have a simple set-up for your equipment and you can start the music.