FOR A PC:
There is a little oval at the bottom of your screen, more to the left, that has an upstairs sighn on the top and a downstairs sighn on the bottom. Click the upstairs button while your in build mode and it should have an outline of a flooring, choose a flooring and put it where you would like it. Now make walls on the outside of the flooring and add rooms and funiture and there you have it, an upstairs. Hope this helped.
You can not build boats in the sims 3
You don't build ceilings.
Yes, you can build your house in The Sims 3. However, building a house in The Sims 3 requires a certain amount of skill, especially for houses with multiple floors.
Unfortunately, you can't actually build stairs/upstairs for the sims on ps2 :'( get the sims 3 or the sims 2 (computer version(s)) to do this. Both work on pc, but only sims 3 works on mac :)
Unfortunately you can not.
Uh...build one?
To find, buy, or build objects from the Sims 3 Exchange, try using cheats.
Elevators are included in the Sims 3 Late Night expansion pack and can be bought in Build Mode.
No, both games are life simulation games.
You can build more rooms in your house and a building depending on your job.
yes, they can be found in the build/buy menu
yes