Changing to new scenes

I have a simple setup that contains three scenes; an opening scene and two main scenes: A and B. The opening scene has two doors - one to enter each scene, either A or B. I want the player to be able to walk through either door and be taken to the respective scene. Ive tried the typical application.loadLevel with a collider on the door as a trigger, but it doesnt load the new scene. What am I missing?

 

Make sure the scenes are added in your Build settings

 

you'll want to use SceneManager.LoadScene (https://docs.unity3d.com/ScriptReference/SceneManagement.SceneManager.html) but that should not be causing the problem. what happens instead of the scene load?