To sync calendar data with ATracker data, user needs to enable the calendar read and write in ATracker->settings, and select which calendar ATracker should read / write.
User can override the calendar write on task level as well. Please validate on the task you want ATracker to write back to calendar on the task level in the task edit form.
After configured these settings, ATracker will write task entry back to calendar for all new / updated task entries after the configuration.
User can also convert calendar entry into ATracker entry by opening the calendar entry on Calendar / History tab and then tap "Convert" button on the top right.
After tapping the "Convert" button, ATracker will try to find a matching task with the calendar title. User can modify it and change start / end time and duration if needed and then press "Done".
The converted ATracker task entry will co-exist with calendar entry.