I wrote a small-and-quick tutorial for using LibreOffice Styles. It is intended to quickly let you understand (and hopefully grasp) the concepts behind the use of Styles without having to go through an entire manual.
It briefly covers and exemplifies the notion of Paragraph and Character Styles, Direct Formatting, automatic table of contents generation and chapter rearrangement through the Navigator.
Styles can do much more than explained in the tutorial, but it should get you started saving a significant amount of time.
Download it by clicking on the image or from here: /files/libreoffice-styles.odt