What are the different permission levels for calendar sharing?
By default, all users can view other staff members free/busy time by simply loading the person's calendar in OWA. If a staff member wants to allow greater visibility, they can choose the next option in sharing which is Free/Busy information including subject and location. The difference between the permissions looks like this:
Free/Busy Only:
Contributor - the person can create events on your calendar but can't view your calendar and can not modify or delete any events that have been placed on the calendar. Events can be dropped on your calendar only.
Nonediting Author - the person can create events on your calendar and view your calendar but can not modify any events once they have been have placed on your calendar or delete any of your events. Events created by this person can be deleted but this person has no permission to modify any event.
Author - the person can create events on your calendar and view your calendar but can not modify or delete any events that you have placed on your calendar. Only those events created by this person can be modified or deleted.
Publishing Author - the same permission level as Author but can also create sub-folders. Editor - the person will be able to create and view events on your calendar and will also be able to modify and delete any event on your calendar. You are effectively giving the person full read and write access to your calendar.
Editor - the person will be able to create and view events on your calendar and will also be able to modify and delete any event on your calendar. You are effectively giving the person full read and write access to your calendar.
Publishing Editor - the same capability as Editor but can also create sub-folders.
Once he shares it with you, you'll need to add it to your calendars from within YOUR Outlook: