Print: 
1x box
1x corresponding lid
4x springs (the included model twice)
2x locks
1x backplate

Springs go into grooves on back of lid, lock sis in front of springs.  backplate rests ontop and must be affixed in place, glue is recomended.

once lid assembly is together place lid onto box and thread a piece of filament through the box and lid or a paper clip (depending on preference or printer tolerances).