The Settings pages allow you to specify the Calendaring Options.
You can specify the name of your Main Calendar Mailbox:
You can specify your Work Week parameters: working hours, the first weekday, working weekdays (to specify custom working days, set the pop-up menu to Custom and click the Update button):
The Calendar View panel allows you to customize the Calendar browser:
Your Main Calendar data is used to generate your Free/Busy information. Use the Free/Busy Publishing panel to specify the time period covered by that Free/Busy information: