You reach the Help dialog by selecting Go/Topics/Index from the menu of the help browser. It lets you access various parts of the Qt Designer and Qt Reference documentation fast and easily.
Contents tab page
This tab page gives you a hierarchical view of all chapters of the Qt Designer and Qt Reference documentation. Double-click on a topic to show it in the help browser.
Index tab page
The Index tab page shows a list of topics that are described in the Qt documentation. You can scroll through the list to find a topic you are looking for or enter a search word in the Look For
Bookmarks tab page
On this tab page, you can set and delete bookmarks as well as jump to a previously created bookmark. The list on the left-hand side shows all bookmarks that you have defined; double-click a bookmark to show that page in the browser window. By clicking New Bookmark, you can add a bookmark to the currently displayed page, and by clicking Delete Bookmark, you can delete the currently selected bookmark.