Add, deactivate, and manage term bin types (i.e. types of grading terms) under "Academics" on the Configure page. Term bin types refer to quarters, semesters, trimesters, etc. in the general sense. This page allows you to create the types themselves, but not determine date ranges that go with them. Visit the Term Bins page for that.
Use the button in the upper right-hand corner to add a new type of term bin.
Enter in the term bin type that relates to your school.
Note: Adding new term bin types will not create additional grading methodologies.