added new prefabs, added scene load manager

Assets/Scripts/Startup.cs

@@ -0,0 +1,13 @@
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+using UnityEngine.SceneManagement;
+
+public class Startup : MonoBehaviour
+{
+    // Start is called before the first frame update
+    private void Start()
+    {
+        SceneManager.LoadScene(1);
+    }
+}