"Handbooks" item in the Settings contains the glossary of frequently referred terms/expression which speeds up the ticket creation process. Every field in the ticked could be linked the Handbooks to get new expressions from the ticket. Handbooks speed up the tickets' processing by 3. You can create your own handbooks and fill them with your own expressions and meanings. Then you must link the new handbook to a specific field. Please read how it should be done here.