Download and print all pages of the artwork on Canon High Resolution Paper HR-101N.
Cut along the outlines.
After scoring the indicated lines with a used ball-point pen, fold the sides in.
Apply double-sided tape or glue to the side flaps.
Fold the bottom piece (with the paw) up and adhere to the side flaps.
Fold the top portion down.
Start mailing those letters out with your new envelope!