From http://www.w3schools.com (Copyright Refsnes Data)

XSL-FO Output

XSL-FO defines output inside <fo:flow> elements.

XSL-FO Page, Flow, and Block

"Blocks" of content "Flows" into "Pages" and then to the output media.

XSL-FO output is normally nested inside <fo:block> elements, nested inside <fo:flow> elements, nested inside <fo:page-sequence> elements:

<fo:page-sequence>
  <fo:flow flow-name="xsl-region-body">
    <fo:block>
      <!-- Output goes here -->
    </fo:block>
  </fo:flow>
</fo:page-sequence>

XSL-FO Example

It is time to look at a real XSL-FO example:

<?xml version="1.0" encoding="ISO-8859-1"?>

<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">

<fo:layout-master-set>
  <fo:simple-page-master master-name="A4">
    <fo:region-body />
  </fo:simple-page-master>
</fo:layout-master-set>

<fo:page-sequence master-reference="A4">
  <fo:flow flow-name="xsl-region-body">
    <fo:block>Hello W3Schools</fo:block>
  </fo:flow>
</fo:page-sequence>

</fo:root>

The output from this code would be something like this:

Hello W3Schools