title: How do I unload additive scenes?
body: <p>I'm making a tank battle game that randomly generates new levels after every round. In my game manager I'm trying to have the round started with an additive loaded scene from a random range index and then end by unload the scene and then loading in a new random scene.  However, every attempt I make results in some form of error.</p>
  
  <p>I've been constantly directed to LoadLevelAsync but it seems to just give me more questions that no one seems to answer.</p>
  
  <p>Here's how it's currently laid out:</p>
  
  <pre><code>//Load random level scene
          int index = Random.Range(2, 4);
          SceneManager.LoadSceneAsync(index, LoadSceneMode.Additive);
          Debug.Log("SceneLoaded");
  
  
  //Unload current scene and load new random level scene
  
          int index = Random.Range(2, 4);
          SceneManager.UnloadSceneAsync(index);
          SceneManager.LoadSceneAsync(index, LoadSceneMode.Additive);
          Debug.Log("SceneLoaded");
  </code></pre>
  
  <p>With the way this code is set, it seems to work fine if the new random level is a repeat of the previously used level, but if the called level is different then it gives me an error and crashes.  </p>
  
  <p>Any advice on where to go from here is much appreciated.  I'm not a programmer in any way so simple yet detailed explanations are necessary.  Thank you.</p>