How to add attachments in the appointment editing window:
Click on Add attachments below Attachments.
Select one or several files.
In order to remove an attachment, click the Delete icon.
Tip: You can also add an attachment by dragging and dropping a document from a file browser or from the desktop to the appointments window.
Also see
Creating new appointments
The appointment editing window:
Using the date picker
Setting recurring appointments
Setting an appointment's display
Using appointment reminders
Adding participants or resources to an appointment
Parent topic: Creating Appointments