Need to set up email address
Need in to know to download app on Apple tv
Question marked as
What is your model Apple TV? Identify your Apple TV model - Apple Support
You should sign in to the box with your Apple ID account, which is named by its email address, and has all the proper user details and a payment method.
If you acquired a second hand Apple TV box that has already been set up, then first reset to factory settings, and set it up as new.
If you forgot your Apple ID email address - Apple Support
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Reset or restore your Apple TV to its factory settings - Apple Support