To Dos come in two flavors:
You may show/hide the To Do List by clicking the To Do List button on the lower right, or selecting Show To Do List from the View menu.
You may show dated To Dos and completed To Dos in the calendar.
To show To Dos in the calendar, select BusyCal > Preferences > To Dos, and check the following options:
Tip: Select the options depicted above so that dated To Dos and completed To Dos only appear in the calendar, and Undated To Dos only appear in the To Do List, to eliminate redundancy.
You may create repeating dated To Dos by selecting a repeat interval in the info panel.
All completed occurrences of a repeating To Do are shown in the calendar, but only the next undone occurrence of a repeating To Do is shown. When you complete an occurrence of a repeating To Do, the next occurrence of the repeating To Do will be automatically created.
For example, you could create a To Do on Monday to "Take out the trash" that repeats weekly. Only the next undone occurrence of the To Do will appear in the calendar. When you complete it (or delete it), the next occurrence of the To Do will be created on the following Monday.
Repeating To Dos in BusyCal will sync with iCal, iCloud, and the iPhone (running iOS 5 and either the Reminders app or BusyToDo), as follows:
To Dos displayed in the calendar are sorted by Priority, Due Date and Title.
To Dos displayed in the To Do List may be sorted by clicking on the To Do List header and selecting a sort order.
You can convert To Dos to Events by dragging them from the To Do list to the calendar.
iCloud calendars are type-specific. Each iCloud calendar can contain either Events or To Dos, but not both. BusyCal will indicate a To Do calendar by displaying a checkmark next to its name.