For the matchbox die the score lines are very important for the box to go together correctly without adhesive, which in my mind is the beauty of the box. So to get the well defined score lines I like to use the crease pad. I run my box and slipcover through separately since SU doesn't sell an extended crease pad....yet....
For my box I'm using some DSP from the Love Sparkles Simply Scrappin Kit. Cut 2 pieces one at 3 1/4 x 6 1/2 for the slipcover and another at 5 1/4 x 6 1/4 for the box.
Here's what your sandwich will look like. Cutting pad, die-foam side up, paper, crease pad. Make sure to test it on some paper first. You may need a shim or two make it tall enough to get those well defined score lines.
Fold and all your score lines. To assemble the box, we'll start with the long side first. Fold up on the inside score line then on outside score line fold down toward the inside of the box.
Turn your box and fold the corners in. There are small flaps on the sides, make sure those are folded up. Fold the sides over the corners toward the inside of the box. Your small flaps should show along the bottom of your box.
Do the same to the other side.
Your box should stay together with no adhesive.
Assemble the slipcover. If you want to stamp on it, do it before you fold it together. Fold on all score lines and fold into a rectangle. You will need adhesive on this part. I like to use sticky strip.