The Course Catalog contains all the courses ever offered by your school—past, present, and future. In order to offer a particular course to your students, it needs to first exist in your course catalog.
Catalog courses are "templates" for course instances. They contain the information shared in common by all instances of that course (more or less). This includes things like abbreviation, description, program(s), level (Grad, Undergrad), credits/hours, and so forth. You can also define prerequisites and equivalencies.
Course instances are courses as they exist within a particular academic term. While they inherit the traits you establish in the catalog, they have particular meeting times, assignments, student roster, section number, etc., unique from other instances of that same course.
Read more about the Course Catalog.
If we imported your legacy academic data, review the catalog courses we imported for you. If we didn't import data for you, just start adding courses to your catalog.