The default start day of week displayed on the schedule is Monday - Sunday. You can change to start on any day of the week that aligns with your business. To do this, go to Main Menu > General > Preferences > Start Day of Week.
You get to the Main Menu by clicking on your company name in the top left of screen (first icon from the left)
Click on the dropdown to reveal the Weekday list, change the Day and click the 'Save' button (in the top right of screen). Returning to the Schedule View, you will see the change reflected.