Hi , I`m Jack Perhaps I can help you with this problem
Do you already have an amazon account and code in hand ?
I can see that you came around to look at my reply and perhaps you cannot reply back so i will give you your answer and hope you will rate positively after reading it .
You can register your device through your computer at this address ; http://www.amazon.com/myTV
You can also see how its done through your device(roku) or computer here ; https://www.amazon.com/gp/feature.html?docId=1000776221
If that answers your question please do not forget to rate by clicking on the star icons at the top, then click on Submit so i get paid for my time helping you .Also note that it will not close this post , you can come back here at any time if you have questions. Thank you