When first opened, the DBT Help window displays a top banner area and a topic content pane below. The topic content on the home page is the top-level table of contents for the entire Help system. All the entries in the table of contents are live links into Help.
The top banner shows a Duxbury Systems logo. You can always click on the logo to return directly to the home page from any page anywhere inside the Help system. The top banner also features a Search bar below the logo. This is the native search function for DBT Help, and it provides the most comprehensive and accurate results among the search options available.
The other feature in the top banner is a menu icon. (It appears as a stack of 3 horizontal lines.) This icon opens and closes a collapsible table of contents (TOC) in a pane on the left side of the Help window.
The collapsible table of contents displays the full list of Help topics. It displays only the top level when first opened, but you may "drill down" as far as you like to find a topic of interest. When you select the topic you wish to view, the TOC disappears (but it can be re-opened at will), and the contents of your topic appear in the content pane.
An additional aid to navigating Help appears on the top line of the content pane. This aid is figuratively "a trail of bread crumbs". It shows you the way back from this topic to the top of the Help system. You can click on a link in the trail to move levels up the help tree.
Finally, above the top banner you will find the Apple Help viewer window frame. It contains four icons at the left: Back, Forward, Show/Hide menu, and Export. On the right side it provides an Apple search bar. The advantage of the Apple search bar is that it searches other help books on your Mac as well as this Help when you enter a search there, but generally the top banner search bar is preferred.
About those icons: the Back and Forward icons (left and right arrows) move between help topics in the usual manner. Each time you hit the Back icon it jumps to the previous topic you visited during this Help session. And the Forward icon jumps you forward again from any jump back.
The Apple Show/Hide menu icon has been enhanced to open the collapsible table of contents. And the Export icon provides a standard Apple option for printing topic material.
Finally, Duxbury has built in 3 custom keystroke shortcuts for you.
Ctrl+Option+H - brings you the root of DBT Help.
Ctrl+Option+T - opens and closes the collapsible table of contents.
Ctrl+Option+U - use this to go one level up from your current topic (but only when there are "bread crumbs" up from your current page).
Keystroke shortcuts only work when the focus is inside Help, not in the Apple Help Viewer frame. You can move from the frame into the DBT Help window using Tab or Shift+Tab.
When you first enter the Help window, VoiceOver focus may be on the Apple search box (not, generally, the search you want to use). This behavior is not consistent.
When VoiceOver is running, all the keystroke shortcuts change from Ctrl+Option+ to Ctrl+ only.