After you have created an appointment, you can attach documents. To do so, click on attachments:

By clicking on Add Attachment you can select single folders in the document tree. All documents in this folder are available to download in connection with this appointment. Every user, who has reading rights of the calendar and who can thus view the appointment, has the option to download this documents. Editing of the documents, however, is still only possible in the download-sector. Edited documents are immediately updated at the appointment.