The Courses form is used to record the name and distance of a course together with a description. You can add as many Courses as you wish.
When you add a Training Session, you will be able to select the course that you ran from a list, and the course details will be added to the Training Session record automatically. This saves you from having to repeatedly enter course details for every Training Session.
It will also facilitate reporting options, by enabling you to search by courses ran and enable you to analyse your fitness progress for a specific course.