Scene changing problem

So I’ve been trying to figure out how to switch from one scene to another within Unity 5.3, but I’m having trouble when I call upon the function that is supposed to load the next scene. The scene doesn’t change and an error pops up saying that:

Scene ‘Scenes/Main Scene.unity’ (-1) couldn’t be loaded because it has not been added to the build settings or the AssetBundle has not been loaded. To add a scene to the build settings use the menu File → Build Settings

I’ve tried changing the name for the scene in the inspector and I’ve added the scene into the build settings, and I still am having trouble. To be completely honest, though, I don’t know what the problem is. I’ve never dealt with scenes (normally, I just make one scene). So, I’ll just provide as much information I can and hope that the Unity Community can help me understand why the scene isn’t changing and the above error is appearing.

Here’s my script for changing scenes:

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using UnityEngine.SceneManagement;

public class MenuScript : MonoBehaviour {

	public Canvas quitMenu;
	public Button startText;
	public Button exitText;
	[SerializeField]
	string m_MainLevel = string.Empty;


	void Start () {
		quitMenu = quitMenu.GetComponent<Canvas> ();
		startText = startText.GetComponent<Button> ();
		exitText = exitText.GetComponent<Button> ();
		quitMenu.enabled = false;
	}


	public void ExitPress()
	{

		quitMenu.enabled = true;
		startText.enabled = false;
		exitText.enabled = false;

	}

	public void NoPress()
	{
		quitMenu.enabled = false;
		startText.enabled = true;
		exitText.enabled = true;
	}

	public void StartLevel(){
		SceneManager.LoadScene (m_MainLevel);
	}

	public void ExitGame()
	{
		Application.Quit ();
	}
}

The scene that I’m trying to get to is named Main Scene.

Within the inspector, I have defined Main Level as Scenes/Main Scene.unity, which is what I copied from the build settings when I added the scene to the settings.

I have not messed around with AssetBundles and I have no idea what they are.

If you need any additional information, please let me know!

Scene ‘Scenes/Main Scene.unity’ (-1) couldn’t be loaded because it has not been added to the build settings or the AssetBundle has not been loaded. To add a scene to the build settings use the menu File → Build Settings

As the error suggests: Open the Build Settings (File → Build Settings) and add the scene to the list.