assembly instructions (mine... after I figured it out), not guaranteed to be 100% correct ...
DRY FIT ALL PIECES BEFORE GLUING ANYTHING
glue top pieces together (JPBtop)
Keys have a hole and post on the bottom. The 'key' track faces towards the outside. glue keys into each end. Be careful, be sure no glue goes into the adjacent track.
put slider with slot (JPBEndSlideWithSlot) into end of box with the complicated key. It does not go all the way to the bottom. Be sure it slides freely up and down.
-- see photo at this point --
glue JPBEndCoverBottom and JPBEndCoverTop to JPBEndSlideWithSlot. Be careful not to get any glue on JPBEndCoverMiddle. It should move freely side to side along the key track..
slide top into place from open side.
One end is now closed. On the other end.... insert JPBEndCoverMiddle peg into slot of JPBEndSlide. be sure it slides freely along the key track.