Have you ever ridden a train in Korea? How was it? Where did you go?
When I was new to Korea, I occasionally took the train to reach areas I couldn't get to. This led me to slowly learn how the train works, and in the process in got lost several times and even took the wrong train.
Being able to ride the train in Korea will open up a whole new world of travel possibilities in Korea. If you're confident riding the train in Korea then you can go nearly anywhere around the country (except places that you need to take a boat). But it works a bit differently than just hopping on a subway, so it's easy to get confused if you're not already accustomed to trains.
This video explains how to get a ticket, find the train, ride it to your destination, and get there on time.