I downloaded some nice beach houses.  I installed one and bought it.  Put it in one of my downtowns.  But the part that was supposed to be ocean was just an empty hole in the ground.

Do you need to put these houses by the ocean?  The three base cities don't have any places where I could do that.  Do I have to create a new city?  

If so, can I move my sims from the other cities to the new one?

What expansion packs do I need?  I tried installing, after having downloaded all the meshes, but it says that I do not have the right expansion packs installed.

I would appreciate these details given.