Stack and align two 3mm basswood boards on top of each other. You can secure them, to be sure all the edges match, but that is not necessary, as long as your cuts are inside the edges of the material. (pic. A)

Set every layer in the file to "ignore", except the Outer Cut layer (100/13), and send it to the laser.

After the cuts are complete, remove the cutoff, and one of the cut pieces from the machine. Make sure the remaining piece is properly aligned, and reset the distance and perimeter markings.

Set the Outer Cut line to "ignore" and everything else to "output." Make sure the Alignment Marks layer is set to Score (50/150), and the Interior Cut layer to Cut (95/14). Send it to the laser.

Place tape on the backside of the bottom piece, carefully align the two pieces of the jig and fold the tape over the edges, onto the top piece to ensure they stay aligned. Press the tape on firmly. (pic B.) This is important, to ensure that when you use the jig, you can properly square it in your machine.

Unfold the pieces along the taped edge. Apply glue to the back of the piece with the interior cuts. (Wood glue is recommended. I did not have any on hand, so I laid down a bead of CA glue). (pic C.)

Fold the pieces back together, making sure all edges are properly aligned. Place some weight on the pieces, and wait for the glue to dry.

Align the jig in your machine, load the card blanks, and engrave your prefered design!