Build a 2 story house on sims xbox 360

[praisedancer74]

 .. Ok someone has to break it down to me very simply (hahaha) on how to buikd a 2 story house on sims3 xbox 360...I try to add foundation and it says "Can't level terrain" so when i go to level the Terrain it still won't let me add foundation and then when i go to raise the foundation to build on a slope it only lays down a small square here and there.. I'm so frustrated...ggggrrr


 Someone please help