UDO can manage one (!) appendix. The contents of the appendix has to be used inside the appendix environment. This environment is started with !begin_appendix and finished with !end_appendix.
Chapters that are part of the appendix are enumerated using letters instead of numbers. A short example:
!node A chapter outside the appendix !begin_appendix !node A chapter !subnode A section !subsubnode A subsection !subsubsubnode A paragraph !end_appendix
The table of contents should look like this:
5 A chapter outside the appendix Appendix A A chapter A.1 A section A.1.1 A subsection A.1.1.1 A paragraph