Open your Outlook and minimize it. Click the "Add Event" icon. The event will open, allow you to save, or put the event directly into your calendar, depending on your email program. If you open the event, just click save and the event will be added to your calendar. If you save it to add later, just click it and it will be added directly to your calendar on the correct date.
Note: Certain browser security settings may need to be changed to allow your email program to accept the calendar event. If you are requested to allow the addition, just accept the suggestion.
If you are using another email program other than Outlook, follow the directions for adding an "ICS" calendar event.