Open the "Books" section, create a new book clicking the '+' button at the bottom of the window, then fill the fields as follows:

• - Book Title: Biferno
• - Book URL: http://www.tabasoft.it/biferno/documentation/reference/index.bfr
• - Cover Image: use this image »
• - Use For Mode: Biferno
• - Search URL (important): http://www.tabasoft.it/biferno/documentation/reference/index.bfr?key=*

If "Search URL" is set, double-clicking (with command key) a word in a bfr file will show the relative reference result page on this site.