Create a forum with ratings enabled. Set the rating aggregate to average. Go to the course capabilities and make sure that students can submit ratings. Filter on the word "rate" and it should be apparent which capabilities they need. They are moodle/rating:rate and mod/forum:rate. As a student and as teacher/admin post in the forum (ie you should have two posts, one from each user). When viewing the other user's post you should be able to rate. Check that no submit button is visible. If it is, you have ajax disabled so turn it on. Each user should be able to rate the other user's post. Student should not see an aggregate. Teacher/admin should see an aggregate that is updated after they submit a rating.