Where should I put the authorization_code for Google authentification?

Hi!I am trying to log in using Google authentication and the application is working up to the point where I get a code which should be inserted somewhere in the application.I believe it is a grant_type also by the name of authorization_code that has to go along with the token uri.I have no idea what to do with it and I can't find any useful tutorials that could make me understand what to do with it.I understood that is a code that acts like a two step authentication which in return will provide you with a token for authentication,but how can i use it in my code??? Where should I paste it? Should I use a method to do it automatically?If so,how can I achieve this?I apologize if this question is stupid,but I would really appreciate the help as this is my first time when I am working with external authentication providers.This is the method for google authentication in xamarin:

`  public async Task GoogleAuth()
        {
            auth = new OAuth2Authenticator(
            clientId: ClientId,
            clientSecret: ClientSecret,
            scope: "https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/userinfo.profile",
            authorizeUrl: new Uri("https://accounts.google.com/o/oauth2/auth"),
            redirectUrl: new Uri("urn:ietf:wg:oauth:2.0:oob"),
            accessTokenUrl: new Uri("https://www.googleapis.com/oauth2/v4/token&grant_type=sOqjxpYQUrHKC-c0nckLxLvyvFXOZ2ffVsAbzK0"),
            isUsingNativeUI: true
            );

            auth.Completed += Authenticator_CompletedAsync;
            auth.Error += _authenticator_Error;
            AuthenticationState.Authenticator = auth;
            var presenter = new Xamarin.Auth.Presenters.OAuthLoginPresenter();
            presenter.Login(auth);
        }
`

In the accessTokenUrl I pasted the code as grant_type but it keeps generating new code every time I run the application which I believe is normal.Can someone please help me understand this?Any help would be appreciated.