This video shows how to quickly import grades that you have from an Excel file into your D2L course. It involves quickly exporting student information with one blank grade (the one you want to import), filling in that column with the Excel data you have, removing unnecessary columns, and importing into D2L.

NOTE: In newer versions of D2L, you don't have to delete the First/Last name columns.
Also, I usually save my csv file on the desktop as a.csv, since it's easy to find. Every time I have a new import/export issue, I save as a.csv, save over the existing file, and know where to find it to import it back into D2L.