When it's necessary to block certain working hours or days because of absence of the physician, you can this by opening Menu > planning > blocks.
When you need to block multiple days in a row, for example for a vacation or business trip, you can use the option 'multiple-day block'. Click the option 'add block'. Next, choose the correct period, hours and a name the block (e.g. "Vacation")
If it's desirable to block single hours or a single (part of a) day, you can choose 'single-day block'. For example if the physician needs to attend schooling between 15-17 hours. Choose 'add block' and start adding the correct day and time. Of course you can name the block to provide better insights to the calendar.