An online orientation gives each new employee the opportunity to hear and see the same material, the same way, regardless of how much time their supervisor has to spend with them on their orientation day.
You can rest assured knowing each employee must spend the required amount of time in each lesson, and will not be able to advance to the next lesson until they have successfully completed a review exercise.
If the employee does not complete the review exercise with a perfect score, they can retake the lesson before again attempting the review exercise.