What he is trying to make is a 3 sided box (open top) with the dimensions shown on the bottom square, although I don't see a depth measurement.
The top, open side would have a strip across the middle (6"wide) with the described holes in it, and possibly vertical walls to make compartments on either side.
I'm guessing he want's to do it all on the CNC, flat-pack construction style.
I'd whip up a file, but I am just leaving for work.
Distinctive Dimensional Concepts Ltd.