- Create your event in Outlook - whether for a whole day or for a specific time slot
- Under the Appointment tab, select the "Show as" button:

Generally, those statuses are defined as:
- Free: Indicates you are available for new appointment requests. Tasks during which other appointments can be made should be set as Free.
- Working Elsewhere: Currently out of office, but working. Indicates you are not available for appointments in your normal location, but you may still be able to be contacted for work purposes.
- Tentative: This setting is used to indicate this is an appointment that has not yet been confirmed.
- Busy: Indicates you are unavailable during this time and will not be able to accept new appointments. Private events will always display as Busy to others.
- Out of Office: Indicates you are unavailable during this time; Away from work entirely. This setting is frequently used to indicate full day absences for vacations/time off.