HFViz is a simple visualization app that lets you see the orientation of your vehicle and your RC channels and individually test the motors (after removing propellers!). Unlike the more sophisticated Betaflight Configurator and Ardupilot Ground Control Station, HFViz is not meant to help you configure your flight-control firmware, since that is supposed to be done using C++ coding.
To build HFViz Windows, double-click on the buildviz.bat file. This will create a new folder HackflightViz folder containing an executable and support files. You can drag this new folder into your Program Files folder or other convenient location.
To create a Favorites icon for HFViz on Linux, run the buildviz.sh script. Log out and log back in, and you should be able to see the icon by typing Hackflight into the Activities bar.