If you've used Font Awesome in the past (version 4 or older) there are some things that you should learn before you dive in.
https://fontawesome.com/how-to-use/on-the-web/setup/upgrading-from-version-4
This package, under the hood, uses SVG with JS and the
@fortawesome/fontawesome-svg-core library. This implementation differs
drastically from the web fonts implementation that was used in version 4 and
older of Font Awesome. You might head over there to learn about how it works.
https://fontawesome.com/how-to-use/on-the-web/advanced/svg-javascript-core