The Course Manager allows you to associate a Subject with the course. Typically a course is within a subject. Example: A course Algebra is within the subject Mathematics.
When you click on the Course Manager sidebar menu, you will see a screen like this:
Click on the gear sign next to Subject. It will open up a table where you can enter a new subject and edit or delete an existing subject name that is taught in your institution.
Whatever subject you enter here will be available to be associated in the Course entry screen,