My working day starts earlier or ends later than what the week calendar shows? How can I change the visible hours?

The hour range that is shown in the week calendar uses the Working Days setting. For example if you have set that your working day is 8:00 - 19:00, then the calendar will display that range. If you want to see more, then widen that range:

Go to the app's settings
Pick an instructor (Studio) or if there's only you, then skip this step (Base/Pro)
Set the days that you work by enabling/disabling the switches
Set the range of hours for your working day
You can also add intervals, for example 9:00 - 12:00 and 13:00 - 18:00, for example to block a break.