Select the D2L Report (.csv) file you created from Instructor Tools (found in Custom Reports). NOTE: If you select the Item Creation box, D2L will create a new grade item when it encounters a new item in the imported file.
D2L will notify you if there are unrecognized usernames in the list you are trying to import. Repair or ignore them and continue the process.
Finally, a preview of your import displays. Click Import to complete the import to the D2L gradebook.