Before adding classes, you need to create a term. To create a term, first open the Terms dialog item by accessing the Settings|Terms menu item.

Create a new term by clicking New
Type in the name of the term in the Term Name field.
Type in the Starting Date and Ending Date of the term in the appropriate fields.
Note: clicking on the black triangle brings up a calendar control.
Create more terms, if needed, by clicking New Term again.
Click Done