Единство следующая сцена
//For C# in unity
UnityEngine.SceneManagement;
....
SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex + 1);
Mage
//For C# in unity
UnityEngine.SceneManagement;
....
SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex + 1);
using UnityEngine.SceneManagement;
int currentSceneIndex = SceneManager.GetActiveScene().buildIndex;
if(currentSceneIndex<SceneManager.sceneCount-1)
{
SceneManager.LoadScene(currentSceneIndex + 1);
}