How do I grade an assignment using a rubric in the legacy grading interface?
This article describes only those details particular to using a rubric to grade an assignment within the legacy grading interface. More options within the legacy grading interface are illustrated in the article, How do I grade an assignment using the legacy grading interface? For information about differences between the new and legacy grading interfaces, see How do the new and legacy grading interfaces differ?
Go to Assignments.

Uncheck the box next to 'Use new grading interface'.
The legacy grading interface is the default setting, but the Use new grading interface checkbox will thereafter reflect whichever grading interface you most recently used. To use the legacy grading interface, this checkbox needs to be unchecked.
Select the appropriate rating level for each criterion.
The points will be added up automatically based on your rating selections. The total points earned will appear in the Grade field below the rubric.
Select Done to dismiss the pop-up window.
(Optional) If you allowed individual score adjustments, you may fine tune the rating points if needed.
(Optional) Select the Comment icon if you would like to include additional feedback.
Enter your comments into the text field provided, and select Done when finished.
Note: The Comments icon changes color when comments are saved.
Save when finished grading the submission.

More options within the legacy grading interface are illustrated in the article, How do I grade an assignment using the legacy grading interface?