I've read Shauna Kelly's excellent article on multilevel heading list formatting, which saved me a ton of time on a recent technical report. However, I'm looking to expand my understanding of heading list formats.

Basically, all I want to do is to have the following format occur automatically:

1.0 SECTION

1.1 Paragraph. Lorem ipsum...

1.2 Much Longer Sentence. Lorem ipsum^2...

2.0 SECTION

I thought there was a way to do this based on some oblique references in old forum posts regarding nested formats for Word 2003 using a paragraph and text formatting style up to a certain point (like a period/full stop), but can't figure out how to do it in practice.

P.S. My home computer is a Mac; I also use Word 2010 for PC at work, and bounce between the two frequently.