Occasionally an instructor will not be in attendance when you arrive for class (for a variety of unforeseen reasons: traffic, sickness, etc.). You should always start class promptly, without the instructor, beginning with prayer and small group discussion.
Your instructor (or a sub) may be delayed but will join you by the time the second hour is scheduled to begin.
If a class fails to wait a full hour for the instructor (using the time as usual for prayer and small group discussion), then students will be considered "absent" and no make-up will be scheduled for the missed class. But if the instructor doesn't arrive in time for the presentation portion of the class, students are free to leave. In that case, the material will be made up at another time and students will be considered "present" for the class.
Thanks for your understanding and cooperation!