Once an order/appointment is created, a notification email is being sent to both merchant and customer including a calendar event file (.ics) to be imported to your calendar of choice.
Default reminders are set as event alerts which can be customized easily.
You can manage the email notifications in:
Sesami > Settings > Email confirmations and calendar events
Google Calendar
We currently have an integration with google calendar and Sesami. For more information, check out our Google Calendar help page.
Appointment Reminders
With our new feature: 
Sesami Flows You can create the notifications such as booking confirmations, reminders, or thank-you messages. Sesami Flow also lets you integrate Sesami with Klaviyo.
Read more: Sesami Flow (Beta)