Thirty six of the cards contain a pair of craps dice. These are regular d6, with spots rather than numbers.
Craps is played in two phases. The first is called the 'come-out'. On the come out roll, a roll of 2, 3, or 12 is called 'craps', and is an automatic loss. A roll of 7 or 11 is a natural, and an automatic win. Any other number is called the 'point'. The shooter wins by rolling this number again, before rolling a seven. If the seven appears before the point is hit again, then the shooter loses.
Because the aim of craps is to roll the same value twice, it is important to shuffle the cards between each roll, if you deal two cards in sequence, there is a much lower chance of rolling your point again (it reduces the chance of rolling a 4 or 10 by a third, for example).
In casino craps anyone can bet on the shooter winning or losing (the shooter must bet at least a minimal stake on either). This is called betting on 'the pass' or 'don't pass'. In addition, there are normally a range of side-bets at different payouts, such as betting on what value will be the point, or betting on whether the shooter will win or lose in the 'come-out' phase. To play a full casino game of craps you probably need a craps layout, where players can place their bets. Even without this, craps is fun to play based solely on whether the shooter will win or lose.
The pass usually pays out even money, and has a 1.41% edge for the house (i.e. over time the person taking the bet will take 1.41% of the bets made). Don't pass usually also pays out even money. But because don't pass isn't paid out if the come-out roll is a 12 (called a 'push') this brings the edge to 1.36% for the house. So the don't pass bet is better than the pass bet, but because you are betting on the shooter loosing, it is sometimes considered bad form to bet this way.