Select the Prerequisites icon to specify which classes must have been completed before a student can register for this class. You will see a screen similar to the following:
Click Add Prerequisite to add a new class to this list. You will see a popup screen allowing you to select a class and click Save to add it.
Click the Remove icon to remove a class from this list.
Note that the system does not protect against circular references (a sequence of prerequisite classes that results in one class being its own prerequisite.)