How to create two slots for the same course.

Step 1. From the main menu -> go to the calendar -> New -> class schedule.

Step 2 - Create the first schedule. Example, 3 hour sessions with daily recurrence. You can add the class name as 3 hour sessions. 

Step 3 - Please repeat the same step (Step 2) to create and schedule with a 4 hour sessions. 

Step 4 - You can now book the students accordingly, or the students can choose the schedule they want and book themselves. You can see both the schedules in the calendar as shown below.