CODE EXAMPLE FOR CSHARP

plays ervices unity sigin

using UnityEngine;
using GooglePlayGames;
using GooglePlayGames.BasicApi;
using UnityEngine.SocialPlatforms;

public class retain : MonoBehaviour
{
    public static PlayGamesPlatform platform;
    
    void Awake()
    {

        PlayGamesClientConfiguration config=new PlayGamesClientConfiguration.Builder().Build();
        PlayGamesPlatform.InitializeInstance(config);
        PlayGamesPlatform.Activate();
        PlayGamesPlatform.Instance.Authenticate(SignInInteractivity.CanPromptOnce, (result) =>{
            Debug.Log("Signedin");
        });

    }
 }