Select your Server in the server list. Then select the Schedules tab and click on the blue Create schedule button. A new window opens.
Schedules use Cron Syntax. This site can help you setup your schedule time. In the example below the schedule runs every day at 0:00 am. Configure the other values as you see fit. Click on the blue Create schedule button if you are done.
After creating the Schedule, select it in the list.
Click on the blue New Task button to create a task.
Done! Now have you a working schedule. You can add as many tasks to a schedule as you want.