This might happen when all of your students haven't accepted your invitation yet.
When you invite a student from your dashboard, they will get a notification in app. Upon accepting the invitation, the student will appear on your dashboard. You can then assign them homework and follow their progress.
If your student needs any help with accepting your invitation, perhaps you can look at their account together next time you see them in class.
Alternatively, your students can contact us directly by submitting a support request if they need help.