How do I gain access to the content of the drive from the Dashboard?
Technically you can’t. The My Cloud Dashboard is for configuring the My Cloud and it’s features/options. It is not a file manager application. Best the My Cloud Dashboard will do is show you how much storage space each Share is using (on the Share tab) and a general overview of how much space certain file types are using (on the Home screen, Capacity section).
If you want to see the user data files on a single bay My Cloud drive located on the local network, then one can use Windows File Explorer or Mac Finder to access those files. For remote access to a single bay, single drive My Cloud one can use the MyCloud.com web portal or the My Cloud mobile app for iOS/Android. Remote access assumes one has properly configured remote access through the My Cloud Dashboard. See the User Manual for the My Cloud for more information on how to access the My Cloud device.