In the beta Version it is not possible to create a individual reminder for a meeting / apponintment. You just can set the reminder for some steps. In the normal Version you can set a reminder more individual. It would be helpful, when it is possible to get the choise for the reminder like now in the beta when you create the appointment with normal settings, and additional it would be very good if you can set the reminder mor exactly in the appointment.
Thank you for your feedback! The deployment for event reminders in the Outlook.com beta is now complete. If you refresh, you should be able to see the experience.
Annette Schmidt commented
It is still quite limited. I have f.e. the choice between 1 day and 1 week, but nothing in between