You can view most details of an appointment in the reading pane. You can turn the reading pane on or off by changing the Arrange Items. If you don't use the reading pane, you need to open the item to view all details. You also need to open the item to make most edits.
To open an appointment, find it in the calendar view and double-click it, or select it and press ENTER.
What if I want to know more?