
Help Builder must be enabled through the Help Builder User Interface before it works in Visual Studio. Currently only Visual Studio 2003 is supported.
Once enabled the Help Builder Add-In provides the following features:
Help Builder integrates into Visual Studio via a new menu bar on the Help menu as well as various Right Click Context menus inside of the Windows Forms and C# and VB.NET Source Code editors.
The Help Menu looks like this:

You can always pop up Help Builder using the Show Help Builder option. Note that Help Builder will always pop up with the last used Help File which may not immediately match the application you are working on. All functionality requires that a matching Help Project is open.
Help Builder always pops up as Always on Top so it's available parallel to your code. If you don't need Help Builder visible any longer you can minimize or close Help Builder.