During registration you can choose to use the pre-booked rooms at Cabinn City: https://www.cabinn.com/hotel/city-hotel-koebenhavn-copenhagen
However if you wish to find your own accommodation, here is a list of recommendable hotels:
Hotels in Copenhagen
Hotel Admiral: https://admiralhotel.dk/en/
Hotel Kong Arthur: http://www.arthurhotels.dk/hotel-kong-arthur/
Ibsens hotel:http://www.arthurhotels.dk/ibsens-hotel/
Hotels in Lyngby
Scandic Eremitage:
https://www.scandichotels.com/hotels/denmark/copenhagen/scandic-eremitage
Sinatur Hotel Frederiksdal: https://www.sinatur-hotels.com/frederiksdal/