To import tasks from Calendar or Reminders into Daylite, you must first enable Calendar Integration. You can read how to enable the integration in the following Helpcenter article:
How do I set up Daylite to sync with the Apple Calendar App on macOS (CalDAV)?
Once you've done that, go to your Mac's System Preferences under "Profiles" and allow access to the Calendar there.
Now, if you copy your tasks to the Inbox in Reminders, they can be imported into Daylite. To do this, select all tasks and copy them to the Inbox by right-clicking. There you click "paste."
Now you have automatically imported all tasks into Daylite.
How do I subscribe to external calendars in Daylite?
How can I share my Daylite calendar?