To connect your Device with amazon.com/mytv you need to create Amazon Account. After Create your Account you Need to follow below steps:-
1 Go to Amazon.com/mytv website.
2 Create new account with "New To Amazon".
3 Fill the form for Registration.
4 Click on the "Crate Account" Button.
5 After click you will Receive a OTP on Registered Email.
6 Conform the OTP and Complete the Process.
7 You will Receive the Registration Complete Message.
After complete this process next step is register Amazon Prime Video service to The Android TV.