I want students to discuss with each other and evaluate each other

Create a new topic-based discussion forum in the course, and put the topic of discussion and evaluation conditions in the header.

Setting up a topic-based discussion forum for scored student discussion:

TipA scholarly and fruitful discussion on a given topic does not usually develop in a course by itself. It may be necessary to set good rules for discussion, to score contributions, to give feedback to students and also, for example, to set a limited period of time when discussion can take place (e.g. a week before a seminar where the topic will be followed up).