People have covered lots of high school culture, so I'll do college culture!
1. Do you guys have Textbooks? Or you just write down the notes that your teacher gives you?
We have expensive books that are either required to even pass the course or are merely supplemental material to help your understanding, depending on what course and department you're in. Oddly enough, the Liberal Arts department requires textbooks, but the Science department does not (unless your professor assigns homework or takes notes out of the book). Our science curriculum comes from PowerPoint and PDF slides, so, if course quizzes and tests come only from these two programs, one can actually get an A without ever buying the book for it.
2. Do you guys have clubs? Like in Japan?
We have many clubs, likely more than American high schools. Dance club, music club, gaming club, anime club, golf club, anything one can think of if one can organize it!
3. What are those lockers for? Where I am living, we don't have lockers.
In highschool, lockers were required, but in college, lockers are optional. Actually, lockers may be detrimental in a sense, because instead of bringing the books from your dorm or house, you'd have to travel to that locker location THEN travel to the classroom.
4. What do you do if someone bullies you? Can you beat them up?
In most cases, bullying isn't an issue in college, probably because people don't have the time to bully people. So if you have that problem in highschool, just picture the future, because it will get better! Bullying is such an isolated problem in my college, we actually have more thefts and rapes, which are already small issues.
5. How do you guys study at home?
[see highschool, multiplied by a factor of three]
6. How do the tests and exams work there?
Mostly highschool, except the special exams. Finals are two hours long, though professors state you wouldn't actually need the full time if you know what you're doing. Biology, Chemistry, and Physics majors have to take a Field Exam if they want to graduate, which consists of material of all required courses. This is like your highschool teacher handing out a stack of papers and stating "okay, what did you learn in 6th, 7th, 8th, 9th, 10th, 11th, and 12th grade, no multiple choice and true/false?" Very, very rough exam, but thems the breaks!