Need help saving a passkey for my Google account

Ok I figured out how to get the my password togo e me the option to login with a passkey. I had to add a physical security key then sign out and back in.
Then a freaking qr code pops up and wants still me to use the devices camera to scan it like google, but how? I mean I could try using my other device that is synced an is my other iphone e with a camera.
So do I scan it like adding a one time password from my other device? That does not work.