Lectures may address as many as 200 or 300 students on some modules. Much of your active learning will take place in much smaller groups, in seminars and classes involving perhaps a dozen students meeting regularly with an academic tutor. These classes provide an opportunity for you to interact with fellow students and academics. The sessions may be used to discuss and explain topics on the course, to develop ideas introduced in the lectures, and to clear up difficulties. They are also meant to develop your communication skills; your skills in working through, analysing and presenting material; and your ability to work effectively with other people.
To benefit from these sessions you will be asked to prepare exercises and complete set reading in advance, and you should be prepared to participate actively in discussion. There is no need to feel intimidated; your tutor will happily encourage you to contribute and present your views and ideas to the rest of the group.