Press the "Daily Puzzle" button on the home screen. The idea is to enter the level and not just the calendar, so if you've already done your free "Daily Puzzle" of the day, you'll have to start another one or wait until the next day if you do not want to spend coins.

Exit without even playing by pressing the top left arrow

Press the "Level X" button on the home page to return to the level that will normally be refreshed