Like a bank card - go to the cashier and have it loaded with a pre-set monetary amount, take the CDC to the table or slot machine of your choice, put it into a card-reader - your bets will be debits from the card and any winnings will be credited to your card. Go back to the cashier to cash out, or maybe transfer the balance to your bank debit card. A screen at the card table will show the bets of all players during games - Chair 1 bets 10, Chair 2 bets 5, Chair 3 bets 100, that sort of thing.