Im an incoming freshman, I have 4 classes on mon,wed,fri and only one on Tuesday and Thursday. Does that mean I have to spend 8-12 hours in between each class or per week? or is it different for every class? How do you have time for things like extracurricular activities and sleeping?
The rule of thumb is that you will spend 2-3 hours per week studying for each credit. So if you are carrying 15 credit hours you might be in class around 15 hours a week and then have to study another 30 hours. But you can also spread that out over the weekends. Some weeks will have more work with deadlines on papers and exams and some weeks will have less.
Typically, you’ll have 2-4hours of class each day, then spend 4-6 hours studying for the next day. So, each day would be like a full-time job of classes and preparation, 7-8 hours. On Saturday you may only study for 2-4 hours, and work hard on Sunday to prepare for the week. So, from Monday to Thursday you’d have to work about 20 hours, and the rest over the Saturday and Sunday. Friday is usually a no-work day, once classes are done people go out, have fun, etc 
You may be able to fly through the assignement, but college requires in-depth work so make sure you devote the amount of tim - keeping in mind also that you have to adjust: if you’re taking Calculus 1 and you’ve already had calculus, you’ll be doing the work faster, but if you’re taking French 1 and English isn’t your native language you’ll need more time to process all the language stuff.