Verify your class list
Click on the Courses button at the top left side of your Digication page
Select the course
Click on the People tab
To add a missing student select the Add Student button under Controls in the right sidebar.
This will take you to a new page where you can Search for Users. Enter the missing student's name or email (using their firstname.lastname@example.org email address)
Once you locate the student
Click the + button in the Add column