firebase authentication with facebook

hi unity community

i am trying to add firebase authentication into my game, but the documentation in the firebase site is a bit confusing. i found this code on the unity forums:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Facebook.Unity;
using Firebase.Auth;
using UnityEngine.UI;

public class facebookAuthenticator : MonoBehaviour
{
    public Text userID;
    private FirebaseAuth facebookAuth;

    private void Awake()
    {
        if (!FB.IsInitialized)
            FB.Init();
        else
            FB.ActivateApp();
    }

    public void logIn()
    {
        FB.LogInWithReadPermissions(callback: onLogIn);
    }

    private void onLogIn(ILoginResult result)
    {
        if (FB.IsLoggedIn)
        {
            AccessToken tocken = AccessToken.CurrentAccessToken;
            userID.text = tocken.UserId;
            Credential credential = FacebookAuthProvider.GetCredential(tocken.TokenString);
        }
        else
            Debug.Log("log failed");
    }

    public void accessToken(Credential firebaseResult)
    {
        FirebaseAuth auth = FirebaseAuth.DefaultInstance;

        if (FB.IsLoggedIn)
            return;

        auth.SignInWithCredentialAsync(firebaseResult).ContinueWith(task =>
        {
            if (task.IsCanceled)
            {
                Debug.LogError("SignInWithCredentialAsync was canceled.");
                return;
            }
            if (task.IsFaulted)
            {
                Debug.LogError("SignInWithCredentialAsync encountered an error: " + task.Exception);
                return;
            }

            FirebaseUser newUser = task.Result;
            Debug.LogFormat("User signed in successfully: {0} ({1})",
                newUser.DisplayName, newUser.UserId);
        });
    }

}

by all accounts on the feed, the code works. however, i do not understand how i would invoke this in my game? how can i get users to fill in their info and pass it to this? do i need a button saying “sign in with facebook” and link it to this script? please help.

it seems that you need to add the method logIn() to your “Sign in with facebook” button listener. I haven’t seen the rest of the code. but hey I am having a problem in building my project!! because of the google jar resolver… can you help me with that!?