How to rename the period and specify its duration (Bell times)

period's edit, belltimes, start, end, period's lenght

Once you add a new period in this way: Can I set the number of lessons per day? you can rename it and set its bell-times (when the period starts and when it ends).
Use the menu: School - Bell times/Rename periods, then select the period and use the Edit button.
In the new dialog you can specify the name, abbreviation (5.) and times of the beginning and the end (6.) of the selected period. You can specify times either by choosing from the dropdown menu or write the exact hour/minutes as you need.

Notes:
- in the dialog Periods you can remove selected period or break. Simply click on "Delete" button. In case, there are already some cards placed on the period, program will automatically unplace them - but not remove completely from timetable.
-please note the checkbox “allow zero lesson:” This checkbox will turn the period called 0 on or off if you are not using it on your school. You don’t need to renumber the 0 to 1 in case you don’t have this special 0th period.