Select the permission/sharing option that best meets your needs. For additional help, see the Permissions Comparison chart.
By default, any campus affiliate using Exchange email and calendar can view free/busy times through the Scheduling Assistant, available when creating or modifying a meeting. You do not need to set permissions or share your calendar.
To allow others, not on Exchange, to view free/busy information you can publish your calendar through Outlook Web App (OWA). Search "calendar publishing" in OWA help for steps.
View Meeting Details
For someone to see meeting details (i.e., subject, location, attendees, description), give that person Reviewer permissions.
View, Create, Modify Meetings
If you want someone to create, read or modify meetings on your behalf, there are two options: Editor or Delegate permissions.