Are you using the Dialogue System's save system? If so, then it depends on which saved game data storer you're using. Here's an example of using PlayerPrefsSavedGameDataStorer and JsonDataSerializer:
var storer = FindObjectOfType<PlayerPrefsSavedGameDataStorer>();
var playerPrefsKey = storer.GetPlayerPrefsKey(slotNumber);
var rawData = PlayerPrefs.GetString(playerPrefsKey);
var savedGameData = JsonUtility.FromJson<SavedGameData>(rawData);
Debug.Log("Game was saved in scene: " + savedGameData.sceneName);
var rawPositionData = savedGameData.GetData("PlayerPosition");
var positionData = JsonUtility.FromJson<PositionSaver.PositionData>(rawPositionData);
Debug.Log("Player position: " + positionData.position);
If you're not using the save system, and if you're only using PersistentDataManager.GetSaveData(), then this function only returns a string. It's up to you to do something with the string. The string is Lua code, so you can print it out to see what it contains. Or you can create a Lua object at runtime and run it through that.
What if you use PersistentDataManager.GetSaveData() during play to record a state. Then save this string somewhere, such as in EditorPrefs or PlayerPrefs.
Add another script that can retrieve this string and apply it using PersistentDataManager.ApplySaveData() during play.
Unlike the Dialogue Editor window, you can use a Lua Console in a build. You can also register your own C# methods as Lua functions and call them in the Lua Console.