If you have read-only access to a Teamup Calendar, when you open an event you will see the details in the event viewer.

The event viewer

The event viewer displays the event details (unless the permission is set to read-only, no details) including inline images, text, links, and attachments (if any). There is a Print option and a Share menu. The event viewer will also show Signups and Comments if they are enabled. 

Note: With read-only, no details access, the event viewer will show only the calendar name and the date and time of the event. The event title will be displayed as Reserved.

The event editor

If you have a higher level of access which allows you to modify events on the calendar, when you open an event you will see it in the event editor. 

The event editor displays all event fields, even the empty ones. Field contents, including the event title and description, are editable. You can adjust the date and time of the event. The Options menu allows you to configure the Signups and Comments for the event. You can see the list of signups, edit or delete comments, and upload files in the Attachments field. 

See more about the different access permissions.