Go to the little box for the levels on the edit screen, then click on make new level. Make a door on each of the levels and for the inside I like using the glowing entry thing. Name them what you want and click lower down to choose where they go. For the “first” one, if that’s the level you are using, then click on the first box and enter your new level. Then click on the lower box and click the door that’s inside your house. For the second one select the one named “first”, and then select your door on the outside of the house. Decorate the inside, and when you exit out the editor screen, you can play with your beautiful house.