We track your grades on a quiz level and on an overall course level. The best way to view your grades is in "My Classroom." To find "My Classroom" click on "courses" then "my classroom."
From there you'll see an opportunity to view your grades at a high level, on a course-by course basis. (Note that courses and tracks will only show here if you've enrolled in a track or course. For more about enrolling in a course, see this article here.)
Your overall grade represents your current grade in that course. It is an average of all your quiz attempts.
To view specific quiz grades within a course, click on the course name and view the grades for each quiz.