A cutting mat, a metal ruler, a cutting knife, a bone folder and a pen. I used the pen for my five inch increments for my shelves to go with dots to mark the spot. I used the bone folder to draw my lines before cutting.
2 poster boards, one for the back of the shelving unit and the other to cut up for shelves and sides/top.
measure your piece of poster board to determine the length and width of your shelves and sides.
Cut 4"w shelves to fit into 5"h spaces as this is the of most of biggest stamps.
Glue the sides and top first to provide stability to the shelves when gluing.