When the internal dividers are complete. Fit into the box.
Assembly of internal dividers. Slot the width pieces into length pieces.
Clip in handle. This requires lifting the handle through the hole. Repeat for the opposite end.
Ensure all box end pieces fit / clip under the handle.
Lower the handle into the end of the box.
Fit a handle into both holes / handle lugs on the sides of boxes.
Bring together both box sides and the box ends together.
Work on one end at a time. Bend up side ends.
Place on your work surface with the side with the heaviest creases facing upwards.