Austin,

If you look here, you will find several tutorials. I suggest you start with the plug-ins tutorial. It will show you -amongst others- how you can edit room points.

Sloping floors aren't possible, unless you use a workaround. The simplest way would be to use a large triangle.
Sloping ceilings are supported; check the roof tutorial.

Also, the User's guide offers a lot of information, as does the built-in Help.

Hans