The tools available to you will differ from Course to Course depending upon what has been enabled/disable by your lecturer.
The calendar displays a consolidated view of all your institution, course, organization, and personal calendar events. You can view events by day, week, or month. You can also view and organize upcoming and past events into categories.
Course calendar events appear to all members of the course. Common entries include upcoming tests, due dates for assignments, or special lectures. Course items with due dates automatically appear in the course calendar. Only instructors may create course calendar events.