Cut on the two middle horizontal lines, and fold in. - Fold the bottom flap up. - Cut the vertical line at the top and fold ...

-- Cut on the two middle horizontal lines, and fold in.  -- Fold the bottom flap up.  -- Cut the vertical line at the top and fold paper in opposite directions to create two flaps.  -- For best results, attach a paper clip to the bottom.  -- Drop and watch it spin!