First GENTLY unfold the box. Be extremely careful not to tear the box. Then peel out the weird foil thingy that is there to hold the gum in place.
Lay the unfolded box onto some paper and trace around using your favourite writing utensil. I used pencil because then I can erase the pencil marks after (Didn't end up doing that anyway but I would recommend it).
Once I cut out the traced picture, I scored it just like the original gum box. That's pretty easy to do except one part. It was so hard I almost died trying to do it............. I had to measure the gum box to figure out how far away the score line on the flappy lid thing was away from the other. Ya right! That was super simple, but if you don't want to measure it, it's a half an inch.