If the students are registered to your course, when they login to ODTU-Class, they will automatically be users of the course. If you want to add a student who is not officially registered to the course, you may follow these steps:
Go to course page.
Click "Users" from the Course Administration.
Click "Enrolled users" from the menu.
Click "Enroll users" button on the top right of the list.
A pop-up window will appear. Type username or id number of the student in Search area.
Find the corresponding person from the presented list and click to select.