Incheon Airport to Jamjindo Ferry Terminal
Method 1 : Bus
Take buses at bus stop 6 or 14 (3rd floor) : bus 222 (7:20, 8:20, 9:20 ~ 19:20), bus 2-1 (6:50, 8:50, 9:50 ~ 19:50).
Ferry terminal is the last bus stop. It costs 1,300 KRW.
Method 2 : Maglev train
Please go to Incheon Airport Train Station and take Incheon Airport Maglev Line to Yongyu Station (Magnetic Levitation train).
http://www.airport.kr/pa/ko/d/3/1/6/index.jsp (Korean Website)
The Maglev train leaves the airport every hour 00,15,30,45 minutes. It is free and takes 12 minutes to Yongyu Station.
From Youngyu Station to Jamjindo Ferry Terminal: Walk 20 minutes (1.2km) or take bus 222 or 2-1.
Ferry
It costs 3,800 KRW and takes 10 minutes to Muuido (Keunmuri).
First ferry leaves at 7:15 and last ferry leaves at 19:45.
(From Muuido, first and last ferry leaves at 7:00 and 20:00)
Muuido (Keunmuri) Ferry Terminal to Home Plus Academy
Take a town shuttle bus after you get off the ferry. You should tell the driver that you are going to "Home Plus Academy". There is no bus stop.
Or walk 20 minutes (1.2 km).
At the Google Map, you may find HomePlus Academy by "Tesco Training Academy". ("Home Plus" is the brand name of Tesco in Korea)