From Oslo Airport, take the regular train ("Vy", not the airport express) to Oslo Central Station: this takes 25 minutes. Use the "Ruter" app or buy a ticket at the machine.
From Oslo Central Station, take the Metro ("T-bane") line number 1 (toward "Frognerseteren") for about 35 minutes to metro stop "Voksenkollen", then walk for ~15 minutes to the hotel. The cost is NOK 40, via the "Ruter" app (www.ruter.no); this is already included if you just travelled from Oslo Airport.
A taxi can be booked (30 minute ride). Approximate cost is NOK 400 (EUR ~40). See https://www.oslotaxi.no
