A. Section tagging for Html documents

B. Using Native scripting

1. I have built collecting when I build and preview under button Search
my documents are displayed as follows: one document appears double in a
paper format not a book.
I would like them to appear just one document in a book format.
I have tried to follow the instruction in under section tagging for Html
doc. Every time I try to build an error message comes up which says:
Argument title_header is invalid
The bad argument occurred in plugin structured Htmlplug