save scene and load using binary file

Hi, my game doesnt have main menu, just simply levels, when players opens the game i want to continue from last session scene(level) . how do i create binary file(or using playerprefs) . could you please help me how to save scene and load here in my game using binary file. here is my game code. please help me i am stuck here for last few days

public class PlatformBuild : MonoBehaviour
{
    void Awake()
    {
        LoadLevel();
    }
public void LoadLevel() 
    {
    
        float spawnPosZ = -42.86f;

        for (int i = 0; i < PlatformsSize; i++)
        {
            GameObject platform = Instantiate(RandomPlatform, transform);
            platform.transform.localPosition = new Vector3(0, 0, spawnPosZ);
            platform.transform.localEulerAngles = new Vector3(0, 0, UnityEngine.Random.Range(0, 360));
            spawnedPlatforms.Add(platform);
        }   
        GameObject finalPlatformInstance = Instantiate(finalPlatform, transform);
        finalPlatformInstance.transform.localPosition = new Vector3(0, 0, spawnPosZ);
    }
}

this is my gameManger script,

public class GameManager : MonoBehaviour
{
       
 public void NextLevel()
    {        
        LevelCompletedMenu.SetActive(false);            StartCoroutine(LoadFade(SceneManager.GetActiveScene().buildIndex + 1));

    }

    public void RestartLevel()
    {
        score = 0;
        StartCoroutine(LoadReStart());
        GameOver.SetActive(false);
        StartCoroutine(LoadFade(SceneManager.GetActiveScene().buildIndex));

    }

}

This is one of those things where there is no one solution. It depends what data you need to store for which objects. I’d look up some C# guides on Serialization, and saving objects to file.