You should install an app such as Bluefire or Aldiko, or for Overdrive if it is just for library books.
I don't think the device will actually show up in Digital Editions (ADE).
For non-DRM books you don't need ADE at all.
For DRM books you need to make sure the app is registered to the same AdobeID as your copy of ADE.
You can than
- get books onto ADE in the usual way,
- 'sideload' the .epub to the Galaxy; eg copy using a file manager such as Windows Explorer or Mac Finder
- read the books on the Galaxy.
Good luck.