What is summer school like?

So I am going to summer school for English and Science in 7th grade. I have class on Monday but they really didn't tell us much about it. I'm bringing a binder with two dividers fro my classes. I was just wondering what is it like? I know it is different for each school but It says in the papers that school is 4 hours long. If I'm only taking 2 classes do you think I will be there for the whole 4 hours or maybe just 2? And i was wondering do I really need to bring a lot of stuff with me like regular school? I'm sorry it's a lot to answer I'm just trying to get an idea of what it's like so i wont be confused.