You can schedule a playlist by selecting a playlist on the left sidebar OR selecting a time slot on the calendar to begin.
A popup will appear where you can set up your playlist schedule: Select the playlist you want to schedule in the drop down, select a start date/time and end date/time. Each playlist must be scheduled individually within the day
You can also set up the selected time by typing the time in your keyboard instead of the drop down. Click on the time field and enter the time you want (e.g. 08:00am).