University is very different to school.
You normally get a soft start with fresher or welcome week where they introduce you to all the key staff, university policies, and you learn your course structure & first semester modules. Universities are typically quite flexible and lenient at the start as they know that this is a transition period. Teaching is normally conducted via a series of new methods for students, largely lectures, seminars or tutorials, and some cases labs or practical element. Like school, where different teachers have different styles and different classes feel different every lecture or seminar will feel different depending on the lecturer or professor, you will quickly learn what is normal and what to expect.
Timetable and can very quite a bit depending on whole hosts of factors but typically you’ll find your course in person activities will be between 9 AM and 6 PM. Most students receive roughly 20 to 30 hours per week in first year and these typically occur Monday to Friday, as your degree progresses you typically move towards lectures, and less towards seminars but again this fluctuates course to course, typically you also get slightly less in person contact after first year.
Yes you do get support however, you get far less one-to-one interaction or opportunities to discuss granular detail than you would do with the teacher in school and the onus is far more put on the student to seek support and make sure that there is relevant time, for example, if you go, the week a big coursework is due and ask for an hour of a professors time (when everyone is bombarding them with questions) you’ll probably get told no (or may not even get a response) yet if you go the start of semester and ask for a moderate time to discuss something specific from a lecture you’re struggling with they are almost certainly going be much more flexible and this is what you have to learn at university, how to manage your resources & responsibilities. You will be expected to be the adults and take responsibility, but you also be expected to realize that unlike in school professors and university staff are juggling a lot of other commitments that could be multiple modules, research (active contributions as well as managing staff, writing papers, going to conferences) and then a lot of other research group activity & admin, and university administration, as well as responding to a cohort of potentially several hundred students and their time is going to be spread much more thinly than with a school teacher who’s dedicated to a class about 30 at a time and only teaching responsibilities. However there is support, you will be given a personal tutor, and you will have a student union so you have levers to support you (as well as building a network of other students).
Exams are pretty similar to secondary school exams. The differences, the scale just a lot more students in exam halls than in school. The other difference is how regularly you have exams particularly if you came from GCSEs/A-levels, where they now come after every semester and you have three or four weeks to prepare whereas in school you probably have more time, and they come less frequently.