You will interact with the authenticators through an HTML page and Javascript using the Webauthn API.
We highly recommend the use of @simplewebauthn/browser. This library provides lots of easy and useful features and it fully compliant with the specification.
If you use the Symfony UX, you may be interested in the Stimulus Controller.
Note that is mandatory to use the HTTPS scheme to use Webauthn otherwise it will not work. This is also mandatory for localhost.