How Do You Register a Device With Amazon?
To sync a device to your Amazon.com account, first download the Amazon Appstore or Kindle Reader on that device. When opening the app for the first time, you're prompted to sign in to your Amazon account. Once this step has been completed, the device is automatically added to your Amazon account. Devices can also be managed by going to My Account on the Amazon.com home page, scrolling down to Digital Content, and clicking Manage My Content and Devices.