This page will show you how to access the Grader Report where you can edit students grades
If you are using this to enter marks it should be used for 'grade item' activities i.e. offline activities like exams. See Recording Exam Marks in Myplace for more information. To upload marks from a spreadsheet to grade items please see Bulk Upload of Marks to Grade Items
It can also be used for quick editing of assignment marks, but to use the full interface available see Simple Direct Grading in a Myplace Assignment and Annotating an Assignment