Setup.cs

using BepInEx;
using UnityEngine;
using UnityEngine.SceneManagement;

namespace RandomizerMod
{
    [BepInPlugin("ru.Mxyfell.Randomizer", "Randomizer", "1.0.0")]
    public class Setup : BaseUnityPlugin
    {
        public static Setup Instance;
        public AudioSource audS;
        void Start()
        {
            Instance = this;
            SceneManager.sceneLoaded += OnSceneLoaded;
        }
        void OnDestroy()
        {
            SceneManager.sceneLoaded -= OnSceneLoaded;
        }
        void OnSceneLoaded(Scene scene, LoadSceneMode mode)
        {
            GameObject System = new GameObject("System");
            System.AddComponent<Generate>();
            System.AddComponent<EventSystem>();
            audS = System.AddComponent<AudioSource>();
        }
    }
}