You can buy a myki card either at a myki machine at a train station or at a 7-Eleven, where you can also load your card. Once you have your myki card, simply hold it up to the card reader when boarding the streetcar, train or bus. When leaving your destination, you will need to swipe the card to ensure that only the distance traveled is charged. You need to top up your card regularly and you can check your balance and transaction history at any myki machine or online.