Purchase your ticket at either a self-service kiosk or the service desk. The fastest option is to use one of the automated kiosks. Kiosks are located in the baggage claim area and in the main area of the airport when you turn right after exiting Customs/Nothing to Declare. If you are uncomfortable using a Norwegian machine or Norwegian money, purchase your ticket from the desk located by the self-service kiosks. The line for this service can be quite long if several flights have recently arrived.
Continue to the right and walk all the way to the far end of the airport once you have your ticket. Take the escalator down to the train platform.
Stow your luggage in the provided racks in the train. Enjoy the short ride into Oslo. The train makes one stop in the small city of Lillestrom before entering Oslo. Exit the train at either the new National Theater stop or the Oslo City Center stop. Check which stop is closest to your hotel or hostel. In addition, both stops connect to other train, tram and bus lines that run through the city.