Cut what ever 3/4 inch material you want to use to a 4" square. I had best luck with 3/4 hardwood plywood but also used 3/4 inch purpleheart
Clamp material to the work surface on the conners. Using 1/8 straight flute end mill zero the work piece on the bottom left corner. Run the carve, I used the recommended cut settings and they worked just fine.
Once the piece is done carving cut the tabs with knife or small saw. Sand in between all the cuts in the part, i did this by hand with 80 grit sand paper. The 2 outer edges of the piece need to have about 3/8" sanded back at a 45 degree angle to allow the battery to fit all the way. Then from the bottom of the piece countersink the 3 holes until the heads on the screws you are using will sit flush with the surface
This battery mount works best if mounted about 3" back from the edge of the shelf or bench, this allows the front of the battery to sit flush with the edge. I used 1-1/4" #10 screws to mount it.