The GnuCash Help Window uses YELP to display DOCBOOK versions of the help documents that are installed with GnuCash.
This window is accessed by going to the Help menu and selecting either the Tutorial and Concepts Guide or the Contents (F1). Help Menu
The Help Window has a toolbar for navigation. The toolbar is described below;
Back Used to navigate to topics previously viewed.
Forward Used to navigate to topics previously viewed.
Help Used to access various GNOME Help files.
Search Enter search term to search GNOME Help files. Does not search GnuCash Help file.
The right side of the Help Window displays the currently opened help page. The left side of the Help Window contains the help Topics list tab. Selecting one of the help topics will load that page on the right side.