The course calendar is the most common starting point for students. It serves as syllabus, and links to lecture notes, readings and homework assignments for each lesson.
The course outline shows the macro organization of the course. It includes links to each of the lessons as well, through the course calendar is more useful day-to-day.
The course resources page contains links to a wide variety of pages, both internal and external to the course. Many of these resources are used during lessons, and many of them provide extra information.