You can export your class details, including their email/username, on the Manage Class page.
1. Click ‘Your Classes‘ from the user drop down menu.
2. Click the blue ‘Manage’ button next to the class the student is in.
3. Click the ‘Manage Students’ tab
4. Click the blue ‘Export to CSV’ button. You will then receive a spreadsheet containing the name and email/username for each student.