You can cut it out of solid wood or plywood. The given files are for cutting in 30mm hardwood (I use ash).
You could use thinner stock (no less than ~27mm), but would have to adjust the centre and profile toolpaths' depth of cut.
Everything is cut with a single 8mm spiral downcut bit to avoid tearout. You can also use upcut or straight cutter, but I haven't tested them. Some adjustments might be needed.
Instead of tabs 1mm of stock is left when cutting the perimeter. It leaves nicer edge. Clean it up when rounding over the edges.
Roundover all the edges for comfort. I use 6mm roundover bit in a router table. Could also round them over on a cnc, but for me it's easier to do both sides by hand.