Installation of FPV is straight-forward and follows exactly the same procedures as any other Mac application. FPV is available from the Apple AppStore. Just click on the link to “purchase” and then install the application by dragging the FPV application to your Applications folder.
After installation you should have a new link under Applications. Clicking that link will start up FPV. Follow the instructions to configure the FPV application and then read this page to understand how it works.