Gather cardboard, a ruler, a pencil, scissors or a utility knife, and tape or glue
Measure the size you want for the box
Draw a box template on the cardboard
Include a base panel, four side panels, and flaps for the top and bottom
Cut out the template
Score the fold lines lightly
Fold along the scored lines
Tape or glue the side edges together
Fold and secure the bottom flaps
Fold and secure the top flaps if needed
Check that the box is square and sturdy