On the top tray, trace out holes for plastic cups, then use an x-acto knife to cut out holes for the cups. Use cable ties to attach the cups to the upper tray. Drill 1/4" holes in the bottom of the top tray.
On the top tray, trace out holes for plastic cups, then use an x-acto knife to cut out holes for the cups. Use cable ties to attach the cups to the upper tray. Drill 1/4" holes in the bottom of the top tray.