Let us give you an overview about where you are ("Wangsimni Station") and where you are heading to ("Dormitory"). Because the campus is located in the old neighborhood, the street is winding and you can easily get lost. (You will later find that you can actually walk to the dorm in 25 minutes, though a small campus town and residential area.) Do not try to walk to the dorm, at least for now. Instead, contact a student helper to get assistance, if you are lost. You can use one of the two modes of transportation.
Taxi. This is the mode of transportation most students used last year, which worked out pretty well. In most likelihood, you can find a row of taxis here, in front of the train station, ahead of the airport bus stop. Be sure to take a taxi with a GPS navigator, which almost all taxis in Seoul have.
Print this instruction, and show it to the driver. Be sure to show the driver the first page, where the instruction is written in Korean. The instruction file contains photos of the dorm and buildings nearby, to help the taxi driver to identify the dorm. Here are the photos around the station and the dormitory to help you recognize where you are.
The fare is metered. No tip is expected, or should be asked for, in Korea. Some taxis are supposed to accept a credit card, but most drivers expect cash payment. If the fare exceeds KW5,000, then you can conclude that something is wrong. It is time to get some help by calling the student helper.
Come to the lobby area of the dormitory (for men), and find a student helper in the lobby who will help you check in.
Bus. This mode of transportation is not for everyone. If (1) you travel light, (2) you have T-money card and (3) you are adventurous, consider this option. It is also a convenient way to move from the dorm to the train station in order to travel to other parts of Seoul.
Make it sure you purchase T-money card at a convenient store at the airport, and you have it charged at the convenient store. If you charge T money card KW20,000, you can go a long way, literally from the airport to the dorm, using buses.
See this map. The airport bus will stop at location "A". The train station marked as "D" would be a good landmark, which is just ahead of the airport bus stop.
At location "B", get on a city bus of yellow green color with number 4211, which arrives every 9-15 minutes depending upon the time of the day. Touch your T-money card to the receiver next to the bus driver. The fare will be somewhere between KW1000 and KW2000. Discount applies if you transfer from subway within 30 minutes or so.
It will follow the route marked by purple line in the map, making several stops (generally moving toward the right side of the map). The dormitory which is marked "C" is located between the last and the second to the last stops.
Be sure to touch your T money card to the receiver when you get off the bus. (Otherwise, you will have a problem when you use the card next time, because the machine will think you did not pay the bus fare for the previous ride.)
Come to the lobby area of the dormitory (for men), and find a student helper in the lobby who will help you check in.