To set up periods, you can go to the Administration tab and click on Timetables. 
You can also go to the Edit Course page (below) and click on Periods from the Schedule tab.
This will take you to the Set Up Periods page. Click Add New to create a new timetable for your classroom. From here, you can name your new timetable, select which days of the week it is effective on, customize the name of each period, set start/end times for each period, and select whether each period is schedulable. Click Save once you are finished.
