Planning gets harder when events, tasks, and notes live in separate places. Starting with the calendar helps because time is the part of planning that most clearly shows what can fit.
That does not mean every day needs to become rigid. It means events and tasks should be easier to read beside the commitments already shaping the day.
Harmonise applies this idea by keeping calendars, events, and tasks close, so planned work can account for the commitments already shaping the day.