I made a simple PDF to share as well.
Basically you can make your box any size you wish if you follow my simple tutorial!! The box can be square or rectangular. The height of the box is determined by you.
For my box, I began with a sheet of ART paper, 12 x 18 inches. I wanted my box to be 1 1/2 inches high. Once you have your height measurement you simply score fold lines that measurement along each side and on each side of the center. These lines are in RED in the diagram. Follow the attached diagrams for you cutting lines, shown in BLUE. Fold all scored lines and glue the bottom four corners together to form the box. I used terrifically tacky tape.
For strength I added a chipboard insert and then covered that with an additional insert that matched the box paper. I chose to round the corners of the lid to ease the folding process. It was so great to have the perfect sized box for my gifts.