Please go to your setup page on your menu. There should be instructions, step by step, to help you throughout the entire process. I have copied the below from the Amazon website:
Register or Deregister Your Fire TV
Register your device to make sure you have access to the latest software, features, and functionality that power Fire TV.
Registration connects your device to your Amazon account so you can access and manage your content. It also makes sure your device has access to the latest software and features available for Fire TV.
As part of first-time setup, you'll see on-screen instructions on how to register your device by entering your Amazon account information. You may also be prompted to enter a code on the Amazon website as an added verification step.
If you purchased your device from the Amazon website, it should be automatically registered to the Amazon account you used to place your order. When your device arrives, you can verify that it's registered to you by selecting Settings
> My Account
from the Fire TV menu.
You can also view or change the account your device is registered to from Settings:
- Select Settings from the Fire TV menu.
- Go to My Account.
- If your device isn't registered, a Register option displays on this screen. Select Register and enter your Amazon account information when prompted.
- If your device is currently registered, the name associated with your account displays in this section. If you select it, you'll then see a Deregister option you can use to connect your Fire TV to a different Amazon account. After you deregister, you'll be prompted to register again by entering your preferred Amazon account information.
When you deregister, all of your Amazon content is removed from your device, and many Fire TV features will no longer work.