On the My Classrooms page, click the 'Action' button and select "All Students".
To change a student's class
Click their current class and a dropdown will appear
Select the new class
Select "Save All"
To change a student's email address
Type the correct email in the student's row. Select "Save All"
To change a student's password
Type the new password twice: once in the "Password" box, once in the "Confirm Password" box. (The password should be 6 characters)
Select "Save All"