Yes, @finndt there are several choices to be made. It sounds like your course and assignments have a grade scheme enabled. You can see the details (including the letter-to-percentage ratio) by selecting the appropriate link on the Course Details tab of your Settings page. More information is in the Canvas Guides document How do I add a grading scheme to an assignment?.
Note that each assignment must have a points possible and the overall score or grade for a class is usually a direct calculation: points awarded divided by points possible. If the course has a grading scheme enabled, that calculation is converted to a symbol based on the values in the grading scheme.