A few details about Herlufsholm, where Christian will be boarding.
https://www.bt.dk/samfund/se-videoen-her-er-prins-christians-nye-liv
The school was established in 1565. Before that it had been a monastery for a few centuries. Parts of the monastery is still there, among them the cells the monks lived in.
https://bt.bmcdn.dk/media/cache/resolve/image_1240/image/165/1651559/23730738-munkeceller.jpg
(When the Reformation took place in 1534, the various monks and nuns were usually allowed to stay in the cloisters/monasteries until they died, or there were so few left that they were amalgamated. - They were also free to leave for a Catholic country. - So after a few decades the last monk died and the last monastery was closed. So Herlufsholm may very well have been a monastery until relatively few years before the school was established.)
The church at Herlufsholm dates back to around 1200, and parts of that church is still visible today.
Today the school consists of 600 students from grade 6 to the third and last year of high school. A little less than half of those are boarders.
Each boarding student has a little room, but they are required to to sleep in dormitories. It's lights out at 22.30 - no mobiles after that.
https://bt.bmcdn.dk/media/cache/resolve/image_1240/image/165/1651560/23730741-sovesal.jpg
There are of course a lot of traditions and quirks in such an old school. The use of various expressions. The last year high schoolers are allowed to wear white pants.