Participants in a Pegaz course can only be those who have a valid USOS account which has been entered by the secretariats of units. Neither students nor teachers can change the roles that are assigned to them from above. You may, however, extend the rights of students with valid accounts, including the ability to co-create some kinds of content.
You also have access to the list of participants (in the left side panel, click on Participants) and to the gradebook (in the left side panel, click on Grades) where you can also track student progress and participation in the course.
You can also create subgroups and assign students to them. Please use caution when adding additional teachers or assistants to a course in order to not reveal personal data to unauthorised individuals.