Moving to Japan as a Grade 11 High School Student

I am currently a Grade 11 High School Student in Korea.

My father got a job opportunity that sends him to Tokyo for a year next year (2026), and said I can go with him for a year to finish my Grade 12 there.

Although I speak a little Japanese (Enough to get me in and out of trouble), I don't really know what anything is like there. The high school life, how friend groups are made there, how things work, do I have to keep things to myself and things like that.

Can anyone tell me (in detail if you have time! :)) how it is there as a high school student?