The PC program that works with the Project My Screen feature for Windows Phone 8.1 is now available from Microsoft's servers.
Once you download the program, you will notice it is a full-screen Windows desktop app at default. That means you can't snap it to the side of your screen, etc. However, if you enter Alt+Enter on your keyboard, the program will go into windowed mode on the desktop.
Also, according to website Wmpoweruser.com, you must first activate Project My Phone under Settings before running the newly-installed program. At that point, you need to plug your Windows Phone 8.1 handset into your PC, and then you can run desktop program.
And that's it. You're now able to project your screen to a TV, display, or monitor via USB with Windows Phone 8.1. For more information on what else Windows Phone 8.1 can do, check out our full review of the operating system.