How to...make a ledge for an Art Table

I found this great art table at Goodwill but it didn't have a ledge and all my things kept falling off. When I made my lightbox I used a metal piece and thena metal drill bit to screw it in. But I don't have a metal bit anymore available and so after racking my brain I saw a flat piece of wood at Hobby Lobby and devised a plan to make my ledge