Generally, courses consist of about 6-10 chapters, so if you do one chapter per week, a course can be 6 to 14 weeks long. You will be able to see all chapters at once, however only those with the grey arrow have been activated (i.e. you can access the chapter content). Usually, the course instructor activates all chapters at ones, but it might happen that he or she has a specific schedule in mind and activates the chapters at a specific time. The instructor will inform you about that through the course announcements.
If your course is a self-paced course, you can work and study at your own pace and rhythm. The amount of the chapters is normally about 5-10 chapters. The minimal time frame a course is open is one year, which means that you have at least one year to finish the chapters. You can decide, if you want to have an intense study experience or if you go through the units little by little.
If a course offers an exam: Please keep in mind, that the exams have a determined audit period. If you miss this period, you can not take the exam and you have to wait for the next audit period. Even in a self-paced course.
Please note that there are also scheduled courses too, where the videos are then only successively unlocked.
The workload strongly depends on the course, as well as on how deeply you decide to go into the material. Some require 2-3 hours per week, others between 5 and 8 hours per week. Please keep in mind that the workload is just a theoretical guideline. For that reason, it is normal if your workload differs from the indicated one.
How can I see, if it is a self-paced or scheduled course?
If the MOOC is a self-paced or scheduled course is displayed in the information box of the course description.