Amazon has released a Cloud Drive Desktop App for Mac and Windows.

Quickly Access Cloud Drive From Your Computer
● Easily upload your photos, documents, videos and other files
● Drag and drop files and folders to the Cloud Drive icon
● Right-click any file or folder and send to Amazon Cloud Drive
● Easy download of one or more files and folders from Cloud Drive
● Uploads and downloads run in the background
● Continue using your computer as you normally would, the app can handle restarts and lost internet connections without losing your data
● You can pause and resume at any time

You can download the app from this link.