Can't find Settings to set up Touch ID in Firefox on MacBook Air

Thanks, Jefferson1. I eventually reached out to 1P support. They helped me figure out that the confirmation code would be sent by authy and not by text - where I had been looking for it. Once that was straightened out everything went quickly and I can now access websites on my computer using Touch ID.

I have another question. Is there a way on my iphone to get a warning a day or two ahead of when 1P is going to want me to reenter my pw? Having to reenter at a random time can be pretty inconvenient, especially if I'm not near my computer (where I store my main pw).