Newb using X5, Questions about Setting Floors

[amateurbuilder]

Just started playing with this. In a nutshell I just want to design a general floor plan for a house and run it by some architects I know to see if it's structurally sound. I'm not really looking to gain anything from this but I'm having fun and getting frustrated with a few things. Ideally it's a 2 story house with a full basement. Everything I find says the basement is Floor 0, and it only let me do that once, and I'm not even sure how I did it. Right now the basement is Floor 1 if that's valid.
I've got some stairs set up, ideally one set leading to floor 2, the other leading to the basement. I can't find any buttons or settings that the stairs go up or down, so they both lead to floor 2, and when I did the copy/paste/hold position, the 2nd floor stairs lead right out of the roof. Anybody know what I'm doing wrong here? Additionally, in this program, what's he difference between a stair, and a stairwell? The 3D views made the stairwell seem like an empty hand rail.