It won't teach Geography or Mathematics but how to fight. To attend the school you have to pay of course, but if you don't have money and still want to attend you just have to do some tests to see if you are good at fighting. The students choose one weapon to specialize. but they still learn the basics of other weapons. Students start the school at the age of 8 and they choose their special weapon when they reach the age of 11.
Most of the students are from Districts 1,2,3,4 but there are still students from districts like 5 or 7 if their parents can afford their "education".