How to create a period of time
To create a period of time:
1. Click on the New period button
2. From the From  scroll down menu, select the start date of the period
3. From the To  scroll down menu, select the end date of the period
4. Tick the All day  checkbox if the period is for all day. If it is only on specific times, untick the All day  checkbox and set start and end time from the days scroll down menus 
5. From the Repeat  scroll down menu, select
- do not repeat, if the period should not be repeated
- repeat every, if the period should be repeated
6. Set how often the period should be repeated, for example every 3 days, weeks, years.
7. From the Repeat until  scroll down menu, set until which date the period should be repeated
8. In the Description field  input a description for this repeat period.