Heya! I completely understand the urgency with wanting to join in on the VR experience. However, the reason you're seeing this error and can't use the app is due to the fact that you don't have the hardware for it yet. While it would be awesome to be able to use VR apps right on your desktop, that isn't a feature at this point. Once you receive your hardware and get it set up, you'll be able to get in Horizon Worlds on your headset!