Use weekly periods when the lessons in questions are to be scheduled at the same time in the timetable on a weekly basis. Use yearly periods if the periods are to be scheduled on an irregular basis.
Note:
You can subsequently convert weekly periods to yearly periods if you enter a '*' in the column Yper.

The following prompt will be displayed if some of the weekly periods have already been scheduled:

Option 1: Convert scheduled periods to yearly periods
If one period of a 2-period lesson has already been scheduled in the timetable, this weekly period will be converted into yearly periods. In the example below these are 20 yearly periods since the school year has 21 weeks containing one week of holidays.


Option 2: Extrapolation: convert scheduled and unscheduled periods to yearly periods
This option results in 40 yearly periods - 20 periods are already schedule and a further 20 requiring scheduling.

In both cases the yearly periods can now be moved as 'individual appointments'.

