Then cut a 5" x 10" sheet of card stock (coordinating, as this will be the inside of the box)
Glue the 5'x 10" sheet of card stock to the center of the inside of the 12"x 6 1/2" sheet
Next, fold the ends over and glue them down as shown below.
Now, take the paper and find two center folds on each side of the X line, only cut down both sides to the second square.
Follow the video, it is a lot easier to explain than to try to write it out. I hope this will help.
Assembly of the inside of the Stair Stepper Box
Once you have finished making the inside boxes, you can begin to assemble your stepper box.Starting with the bottom box, using a strong glue, glue it to the bottom of the outside box on just the one side of the small box, on the first fold next to the small tab, as shown below.
Then space your next boxes on the next folded tab at about 11/16" up from the bottom one.
Keep gluing each box on the next tab at about 11/16" from each other,so that you have the "stair step" effect and all 4 of your boxes are firmly glued.