How do bridge bidding boxes work?
Each box contains a set of cards, one card for each possible bid. The cards are kept in the box in order of bid, from the lowest to the highest.
To make your bid you remove the card containing the bid you want to make, along with all the cards behind it. Place the cards on the table, with the card displaying your bid on top.
At the end of the bidding, simply pick up the stack of cards and replace in the box, behind any remaining cards.