Hi again Giang
The JDocBook and Publican Interoperability chaper has what you need I think. The section named Install Publican has links to Section 4.2 Publican. This section directly preceedes the JDocBook/Publican section.
This whole chapter is for JBoss Community projects that want to ensure their projects build using JDocBook and Publican. If your project does not want to do this, then you don't need to follow the instructons.
It's also worth noting that the docs.jboss.org/author Confluence wiki system outputs XML documentation to a publican-ready format, providing you follow the authoring guidelines.
What project are you working on Giang?