It's a beautiful building. You can enter from above from the street by a separate staircase and a beautiful view opens at the top. And there is a regular central entrance. The inscriptions are duplicated in English. There is a cafe inside. There are cupboards for luggage of different sizes. KTX train tickets were taken to Busan without any problems on the next flight. I had to wait 5 hours for the train from Busan to Seoul. Maybe the day of the week was busy? Therefore, I advise you to buy tickets in advance, just in case.
Everything is quite clear. There are placards with train departures everywhere, the main thing is to know the number of your train. When you need to go to the platform, focus on the blue signs with the inscription PLATFORM, and go in that direction, along the way there are railway workers who help with the direction. There is also an electronic scoreboard on the platform itself indicating the train number and direction. The only thing you need to know is DON'T BE LATE!!! THE TRAIN IS LEAVING SECOND BY SECOND!!! NO ONE WILL BE WAITING FOR YOU, AND THERE WILL BE NO OPPORTUNITY TO JUMP INTO THE LAST CAR EITHER!
Nice clean station. There are many recreation areas. On the second floor there are storage cabinets of different sizes. How many decent cafes. Escalators are working from the front in the afternoon. But after 12, you will have to incarnate with a ladder.