How can I add a Facebook login button to my site?

Store Design
1

I would like to add the Facebook Login Button instead of using the Shopify default plugin.

What I have done:
According to the Facebook document https://developers.facebook.com/docs/facebook-login/web
“B. Log In with the Javascript SDK Login Dialog”, added the code to the page and disabled the Facebook Login plugin from Oxi App. There is an error showing on the console from inspect, please see attached photo for your reference.

Questions:

  1. If I disable the Facebook login plugin from Oxi App, it is hidden or it is removed?
  2. Is it possible to add code to the theme (theme id: 714)?
  3. Where can insert the Javascript SDK in order to add the Facebook login button?