If several people, typically hired PhD students, are involved in teaching a course (e.g. correcting assignments in the homework vault), it is most effective to add them as teachers in the Course Catalogue:
The Information system Teacher [course selection] (Course Catalogue) Edit teacher-related data
All those listed in the course’s Catalogue have the implicit right to manage the course's Study Materials folder and use the Teacher's Notebook, so there is no need to set their access rights.