How japanese clubs works?

Hi, I'm confused about how a japanese public middle and high school sports clubs work.
I found a website with an example of school times.
If a sport club have a morning session about 1h before lessons starts and 3 h after lessons end.
How can a student study? Or more likely when? They study after dinner? But even then they may have 1/2h before they need to sleep.
Or they study just before exams and just pay attention to lessons and a light study?

Oh do they have interrogations and surprises exams or just an exam week?

Also how the gym works? What if more than one club need the gym?

Sorry so many questions 😅