Are you an instructor or a student? Here are the video tutorials for both roles:
If you are an instructor, does the "Grades" course navigation button on the left side of your Canvas course have a crossed-out eye icon next to it? If so, you may need to enable it for your students:
If you are a student, are you not seeing the "Grades" course navigation button on the left side of your Canvas course? If that's the case, then maybe your instructor has hidden this navigation menu button from you and your classmates? This would be something you'd have to discuss with your instructor.
Looking forward to hearing back from you soon.