Your calendar will allow you to book as many appointments as fit into your availability. If your hours are 9:00am-5:00 pm and you offer 60-minute appointments, the last available appointment will be 4:00 pm.
You can set up your hours in Business Settings > Availability.
Regular Weekly Hours
If you work regular weekly hours Monday-Friday from 9:00am-4:30 pm, with an hour lunch break at noon, you would set your hours to "9:00am-12:00pm, 1:00pm - 4:30pm" (be sure to separate time ranges with a comma).