I can't see the Course Menu

In an eLearning course, on the left-side users should see a menu that contains different links to materials in the course. This menu is called the Course Menu and should look simiiar to this:

Course Menu

Users can minimize or hide the course menu which prevents users from navigating within the course. If the Course Menu is not visible, below are the two options to display the Course Menu again.

Minimized Course Menu:

Minimized Course Menu

Hidden Course Menu:

Hidden Course Menu