A note:
"Push Notifications" only work with some services and not all of services have them.
Start here:
Okay, I always get stuck at the QR code; like where is the Amazon QR code found. Or since I do not have a QR code, where is the secret key, whatever that is? This is so complex......
With Amazon you need to go to Your Account on Amazon and then "Login and Security" and Enable:Two-Step Verification (2SV).
iR