General help

As you've already set up the assignment, you could also go to the Assignment administration > Permissions and add the student role to the "View grades" permission. This will give them access to the Grading table (when you click on "View al submissions"), but as long as you don't add the student role to the "Grade assignment" permission, they will only be able to download the files and view any grades you've added. It's a bit clunky, but an easy solution.