Scandic is about 15 min away and of cause the easiest way to get there is to take a taxi from the airport and tell them to take you to Scandic Copenhagen (Vester soegade).
Just go to the train station inside the airport and take a train to the main station (Copenhagen H). This is a 15 min ride and from Copenhaven H you can walk to the hotel in 5 minutes (see the map). Remember to buy a train ticket.
Helpful links:
Travelplan
Airport map
