The Kindle needs to be recognized in order to transfer and manage all the files. If the device is not recognized, access the Devices Manager (Start > Run > devmgmt.msc). Right click the device and choose Windows Update. Follow the instructions presented on the screen to properly recognize the device.
Once the device has been recognized, start the Kindlean and choose the corresponding device.
Additionally, install Calibre which provides additional tools than Kindlean does.