Digital editions doesn't detect anything.

ADE does not generally recognize tablets; though I think a few run ereader software that makes them look like a dedicated ereader device that can be seen by ADE.

For most tablets, you install an ereader app (such as Bluefire, Aldiko or Overdrive) and register that app with your Adobe ID (if you want to read Adobe DRM books).

You then copy books from your PC using your file manager (Windows Explorer, Mac Finder) to the tablet showing as a mounted drive.

Apple devices don't show as mounted drives either (Apple like to make things difficult for their users), so you have to transfer using Dropbox, iTunes or emailing yourself.

Do you mean ipod or ipad?  I doubt you can read Adobe DRM books on an ipod.