Oxford's world leading tutorial systems benefits from small group sizes, up to four students. Classes may have a dozen or so students. Seminars and lectures, especially if given by guest speakers, may be considerably larger, up to fifty or occasionally more. Lectures are generally not interactive, unlike the other formats.
A tutorial is interactive. The more you bring to a tutorial or class, the more you will gain from it. Tutorials are an opportunity for you to raise the issues and ask the questions which are troubling you, and to try out your own ideas in discussion with someone of greater experience; classes are an opportunity to explore issues together, and to get used to general discussion.
For most tutorials, and for many classes, you will be asked to produce written work, and a good deal of your time will be spent writing and preparing essays on topics suggested by your tutors. They will normally direct you towards some secondary reading.
There is tremendous variety in the ways that tutors approach tutorials, and that is a strength of the system. Given this variety, do not worry if your peers in other Colleges seem to be doing things differently for any given paper; your own College Tutor knows how best to prepare you for your course and examinations.
Your tutors will give you regular feedback in the form of comments on your work. It is reasonable to expect written comments on any work a tutor takes in; but it is exceptionally rare for tutors to put marks on written work.
A lecture list will be published in 0th week of each term on the School website here: https://anthro.web.ox.ac.uk/lecture-list
Lectures do not always coincide with the term in which you are writing essays on that subject. Important lectures may come a term or two before your tutorials; in this case you should read in advance the texts which are being lectured on, even if that reading has to be in translation.
Lectures aim to provide a broad overview of fact and theory by experts in particular areas. While tutorials allow students to pursue special issues in greater depth and to develop their own views, together with skills in writing and argumentation, it is impossible to benefit fully from them — or to do well in examinations — without the broader perspectives offered by lectures.