Was there skills taught in these texts, or was it a matter of just being if you could pass the exam you were considered intelligent enough to work in the royal court?
Education trained the cultivated generalist. There was disdain for the specialist and for technical training the prevailed into recent times. Although chapkwa, specialized technical exams, existed for certifying doctors, astronomers, interpreters, and other needed professionals, they remained far less prestigious; education was basicallt of a nonspecialized, literary nature, which has remined the preference of most Koreans. The people who took the specialized exams were largely from the chungin class, not the yangban aristocracy. A History of Korea by Michael J. Seth, p140, Education
Basic education in Korea was provided by the state, and it was very basic. If a person wanted to enter the civil service, they would go to a hyanggyo, a state sponsored school where they studied for the tests from around age 16 until 18. The hyanggo were "usually located in administrative centers," according to Seth, but I'm going to disagree here... I've been to a few of them, and they are in the middle of nowhere. Here is the entrance to a hyanggo (check out the location on google maps - 85 Eupnae-ri, Gyodong-myeon, Kanghwa, Incheon) that is in the middle of nowhere. Of course, HISTORICALLY, before the division of Korea, it could be easily reached via ferry from Yeonan or Haeju, but it's still pretty rural. Here is another hyanggyo, in Yeosu ( 202 Gunnae-ri, Dolsan-eup, Yeosu-si, Jeollanam-do, South Korea) This school is also really rural, but you can get a bit more of an idea of the size. This complex has a total of 9 structures (I'm also comparing it with Google Maps): the caretakers house, a shed, the main gate, an inside gate, then five school related buildings. These would most likely be the classroom, the sleeping area, an eating area, a storage shed, and a back gate.
I don't know a ton about these schools beyond what I've said here. I wish I had more photos and information for you, but, for some strange reason, every time I go to one of these places, I really have to poop and I lose my focus on taking photos. Bathrooms are tough to find around these places! I will try to do better next time, I swear!