Please search address of the Space Duck in the navigation. It takes 55 minutes from Jeju International Airport. There is a parking lot in front of each room, Space and Duck. The duck shape of the Space Duck is a trademark. The left paring lot of that is for Duck and right is for Space.
After taking bus number 755 from Jeju International Airport, transfer to Bus No. 967 at Oseulok Stop and get off at Shinheung-Dong Bus Stop. It takes 10 minutes on foot from the stop to Space Duck. I would recommend to use rental car rather than public transportation because of the inconvenience of Jeju bus.