It takes a while to load, but should run fine once it gets going. (Optimization is one of the things I'm working on as I create more of these.)
It's about how to create cross-references in Writer, and what they are.
Note: The video uses the Navigator (press F5) to get around more easily to various headings being referenced. The Navigator shows you the structure of your document and the objects in it. By "structure" I mean that it shows all the text to which you have applied the paragraph styles Heading1, Heading2, and so on. More specifically, it shows whatever you have set up as the paragraph styles defining your documentBy structure under Tools > Outline Numbering. That's a whole nother topic, though a very useful one. To learn more about outline numbering and the Navigator, see these blog entries.
http://openoffice.blogs.com/openoffice/2006/10/in_praise_of_ou.html
http://openoffice.blogs.com/openoffice/2007/06/using_the_navig.html
http://openoffice.blogs.com/openoffice/2007/06/going_to_a_spec.html
http://openoffice.blogs.com/openoffice/2007/06/leaving_a_trail.html