The large cookie tray and folding hinge brackets came from Amazon
Winware 16-Inch by 22-Inch Aluminum Sheet Pan
Folding Shelf Bracket SP1794 16in x 16in Sold in pairs
Then I used a 1/2" 16x16 piece of birch plywood I had. Attached the plywood to the cabinet with 1" #14 sheet metal screws and used a glue for melamine, which holds good to slick surfaces like the rolling tool chest has. You could also use liquid nails. Next I put one of the folding shelf brackets with the cookie sheet on top to see where I needed to place the brackets, I have the tray just below where the drip tray can slide out without hitting it. Then attached the two folding brackets to the plywood/tool chest again with the same size sheet metal screws. Placed the tray on top of the installed brackets and marked the holes underneath with a black magic marker. Drilled the 4 marked holes with a 1/4" bit and installed 1/4" x 1/2" plated bolts with lock washers and nuts, that was it. very easy and the tray is great to use, I place meat on a grill rack to be placed in the smoker and also bring meats out after smoking and the shelf is nice to place the full grill on, etc. Hope that helps, the Sears craftsman rolling tool chest goes on sale for $99 all the time, either red or black in color. Also spray painted the plywood and brackets with flat black paint to be similar in color as the tool chest.