Choose your students courses, build their class rooms and dorm rooms. Watch them go learn the spells you taught them and use those skills at an end of year competition that includes wand duels, broom racing, alchemy and divination. Take the money you win in these events and add onto your school, hire more teachers, and repair the damage running a magical school will likely cause. Then, keep that up for 6 school years and you might even have a few graduate intact!
This is a test of the duel system. It's working great! Duels have 3 parts, beam attack, magic missile, and charms. Students will cast the spells you teach them, and use the attacks you've helped them prepare until one student faints. Or is transformed into a chicken. Or a statue. Or a gooey mess.