If you haven't done so already, build the circuit in the diagram on Step 2.
There should be a lot of excess wire hanging off of the negative side of the LED. Strip all of it; enough to wrap around all of the holes in the bottom of your board. This exposed wire will act as the "metal sides" that players will try not to touch.
Using the spare pieces of cardboard, we can make holders for these pieces of straw.
Bend the pieces of cardboard, as shown in the picture, and superglue or tape them to the bottom side of your shoebox lid, over the holes.