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.
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.
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
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.