[Note: Here's a template you can use with this, see instructions at end of post.]
You don't really even need to know what this feature is to benefit from it.
For every document, be sure Outline Numbering is set up correctly. You'll get a lot of very cool automatic formatting and content for free.
Outline Numbering is the specification of the structure of your document. It just means telling OpenOffice which paragraph styles you're using for headings.
Why bother with outline numbering? Because when you have outline numbering set up, you get so much cool stuff for free.
How do you do it and what are these fabulous free things?
Step 1: Apply styles to all headings (but you already were, right?)
You must, and should, use paragraph styles with each heading to indicate what type of content, and what level, it is.
Just select your heading text and click in the style dropdown list...
Or choose Format > Styles and Formatting, click the Paragraph Styles icon (far left at the top), then double-click the style name.
Now the selected paragraph style is applied to the text in the selected heading.
It's easy and simple to use the paragraph styles Heading1 through Heading10 for your headings.
If you don't like how the styles look, modify them. Right-click on the style name in the Styles and Formatting window and choose Modify.
Step 2: Check that Outline Numbering is correct (it should be already)
The default structure is Heading1 down through Heading10. Choose Tools > Outline Numbering; it should look like this.
If it doesn't look like this or if you applied different paragraph styles to your headings, then just apply the correct styles to each level. Select a level on the left, select the appropriate heading style in the dropdown list, and so on.
If you want numbering that is like this, then assign the appropriate numbering at each level.
Then change the Show Sublevels field; if you want a heading to show 1.1, for instance, you want to show two sublevels.
Then click OK.
Step 3: Benefits: You get automatic tables of contents, and easy, automatically updated running headers and footers
Now, tables of contents work automatically. Choose Insert > Indexes and Tables > Indexes and Tables. Click OK. TOCs are set up by default based on your outline numbering, assuming it's Heading1 through Heading10.
So with no additional effort at all I get this TOC from the sample I showed earlier. The gray just means that the fields are generated automatically. When you change anything in the document, right-click on the TOC and choose Update.
You also get easy running headers and footers. Click in a header or footer, Insert > Fields > Other, and click the Document tab. Select Chapter as the Type, Chapter Name as the Format, and the level you want. Layer 1 is the current top level heading text that you used the Heading1 paragraph style on; Layer 2 is the current second-level heading text that you used the Heading2 paragraph styel and so on.
I inserted Layer 1 on the left and Layer 2 on the right of this footer. Click to see a larger version. In a few pages when I've got different headings, these footers will change automatically.
See? Outline numbering, and using easy styles for all your headings, gives you a lot of great automatic stuff for very little effort. And we love getting a lot for a little.
Here's a template you can use so that you can have Ctrl 1 through Ctrl 9 associated with heading styles Heading1 through Heading9. Ctrl T is for text body and Ctrl W is for text body indent, also.
Download the template, then set it as your default template. Default Template means that when you choose File > New > Text Document, this template opens automatically.
1. Open it in OpenOffice. It's got some explanatory text in there, so delete that. Also, optional, if you want to edit how the styles look, just right-click on the text for that style and choose Edit > Paragraph Style.
2. Once you're good with how the template looks, choose File > Templates > Save. Name the template and put it in My Templates category. Click OK.
3. Choose File > Templates > Organize, and in the left-hand column open the My Templates category and find that new template.
4. Right-click on it and choose Set as Default Template.
[to go back to the normal template, right-click anywhere in the left pane and choose Reset Default Template.]
Now when you choose File > New > Text Document, you've got quick keys for all the styles, and you can be really fast applying styles.