EditorSceneManager.MoveSceneBefore

public static void MoveSceneBefore (SceneManagement.Scene src, SceneManagement.Scene dst);

파라미터

src	The Scene to move.
dst	The Scene which the source Scene should come before in the hierarchy.

Allows you to reorder the Scenes currently open in the Hierarchy window. Moves the source Scene so it comes before the destination Scene.