The engine is used to make 2D adventure games, so the engine cannot be used to make 3d game. Of course you can add nifty effects to make it look like 3d, but still you are basically restricted to 2d.
There's some basic tutorials in the documentation and you should download the demo game and look at it's sources. The demo game is pretty well documented so it is easy to understand. If there's something you don't get, you can always ask here.
I have understood that Mnemonic has the documentation under way but I wouldn't hold my breath.
