Once you have passed you cannot bid again. The bidding continues around the table as many times as necessary until three players have passed. The player who did not pass is then the declarer and the final bid determines the number of card points the declarer needs in tricks plus the stock in order to succeed. The declarer is entitled to take the stock and choose what suit will be trumps. The choice of whether to give up must be made before looking at the stock.
Some players knock the table to indicate a pass.
On the first round of bidding, if no one else has yet bid, a player can bid 2 blind - i.e. without having looked at their cards. It is not legal to jump bid, for example you cannot begin with 4 instead of 3, nor can you bid 5 directly over 3. The declarer may take the stock without showing it to the other players and discard any four cards face down. The discards may include some or all of the same cards that were picked up from the stock. Card points in the stock will count with declarer's tricks towards fulfilling the bid.