Measure 1 inch from the bottom all the away around the box. Mark with tape. Plan the location of the eight vents that go above the taped area (including two in the lid). The sides need two vents each while the ends need one vent each. Mark where the vents will go on each half of the top. Flip the box over and mark where the two bottom vents will be located.
Cut all marked areas with a hole saw attached to a drill.
Place vents along the sides and tap into each hole. Using a small hammer and/or pliers will aid in forcing them into the bin.
Cut slits in the metal rim of the remaining vents with tin snips. Flip the bin over on its lid and place vents in the bottom holes. Bend the metal rim of the vents over onto the plastic bin.
Set up the tray table in the location where the bin will be placed. Place the bottom of another 12-gallon plastic tub on top of the tray table. Paint the two 1-inch by 2-inch by 18-inch boards. Let the boards dry. Lay the two 1-inch by 2-inch by 18-inch boards across the tub. Place the worm bin on top of the boards.