You will see the bidding box only when it is your turn to bid.
The amber arrow will indicate whose turn it is
to bid — vulnerability is shown in the player's
choose a bid, click its button in the bidding
box, then click the "OK" button.
If your bid is alertable, click in the "Explain" window, type in
an explanation of the bid, then click the "OK" button. Your
opponents and any spectators will see the explanation.
The Bidding History will display a record of the bidding in the right side
of the screen until the completion of the first trick.