As a current student at DIS, you are provided with an SL transportation pass, which is valid throughout your summer in all zones of the SL transportation system. Note that transportation to the airport requires an extra charge to your regular pass.
At the metro and train stations, you validate your transportation once you start your journey by holding it in front of a card reader until the green light shows and a single beep signals that your pass is valid. In the metro and the Pendeltåg, card readers are installed at the entrance to the platforms. If you take the bus, you will find the card readers upon entering the bus next to the driver, and for light rail services you board the train and a conductor will come and check the ticket during your journey.