Using a single loading screen for multiple levels

Hi , could anyone assist , I have tried numerous methods of using a single Loading screen widget for opening multiple levels. I still am stuck on the same page and only having the ability to open only the first level. I am trying to develop a RTS and so far this has been a tough one. Could anyone please assist?

You need to use level streaming. The menu level is the persistent level, and all of your other levels are sub levels. See this tuut: