It works like this:
There are X many players and the dealer is the bank.
The dealer deals 5 cards each to the players.
There are two rounds of betting.
During their turn, each player manifests themselves on betting, and asks or not a card from the bank. Only one. However, they ask for a specific card (number, suit, or both). The bank then looks inside the deck and, if he has the card, gives it in exchange for a card the player discards. If not, the player can stay or keep asking until he gets a card.
At the end of the hand, any player can ask that the bank show the bank deck. All cards are flipped right side up in view of all payers.