Interesting story and concept so far. I'm intrigued as to where it's going. I've noticed only a few minor grammar and spelling mistakes, but otherwise it's very good.
As for the line breaks, you can make a real one if you go to "Edit Document". There's an icon displayed at the top of the document next to the alignment icons - it's just a horizontal line. Put the blinking type cursor at the beginning of the first sentence of the scene change, click on the icon, and a line should appear.

Keep up the good work.

Doctor Smileaway