Premium Guided boxes often have a unique locking mechanism, which make them extra strong compared to standard tuck-top or 'auto-bottom' boxes.
The "1-2-3" locking mechanism on the bottom has extra flanges to hook securely into place, and the wide surfaces provide plenty of support. This structure is very sturdy and reliable, but sometimes it's a little tricky to assemble until you get the hang of it.
Here's a handy step-by-step guided to get you started.
Flip down the only bottom panel that has sharp corners. This will be the bottom of the box, into which the other panels fold.
Flip in the left and right panels so it closes the bottom of the box and then tuck the tabs under the first panel.
Gently indent the tabs on the final panel and tuck them into the center where the other panels meet.
At this point you may be worried about it not fitting together, but a quick tap on the bottom from INSIDE the box will nudge everything into place and you'll have a friction lock that strong enough to handle whatever goodies you place inside.