Right, when you've created a family, you're supposed to choose an empty house you can afford (we may be speaking of 2 or 3 houses at the beginning). Then you use the left stick to guide the cursor over the icon for the right house and click on the accept button (it's the O button for me, but I incidentally have a Hong Kong PS3 which changes specifically that part with many games, so for you it may otherwise be the X button).
You then come to a screen to choose whether you want the house decorated and whatnot. Use the left stick or the black arrows on your left to choose the options you'd like. Press the O (or maybe for you X) button to accept where it says 'accept' or the like.
As for your second question, I don't really understand what you mean. If you mean uploading it to your online studio, then you need to have it saved first in-game, and if you mean the studio in the game, it should save quite naturally and I recommend you do that for safekeeping purposes. Remember that you can't place any other family than the one you're going to play with. If you save the sims, it's only for later use in later saves. Unless you go out of the game before placing the family first of course, then when you come back you should be able to choose a family you've done previously instead of making a new one. I believe it is almost the same system as in the PC.
