Install is pretty easy. After installation is finish, you just need to sign in.
Unlike Dropbox (SkyDrive, Google Drive and Apple iCloud), Cloud Drive Desktop App does not create local folder on your PC or Mac.
Instead, it only creates an icon on your task bar (all of the major players do). To upload file, you can drag the file or a folder to the icon.
You can also right click on the file or foler and select Send to / Amazon Cloud Drive.
In my opinion, I still like the Dropbox style local folder. The Amzaon Desktop App only make upload files easier, but you can not organize the filer on your local file system like all other major players do. But anyway this is a big improvement from the Web interface only choice.