Hi,

It looks like the main issue is that the billboard is not positioned on the virtual floor, but far from it. For detailed instructions on placing the billboard, refer to this guide: https://aximmetry.com/learn/virtual-production-workflow/green-screen-production/virtual-camera-workflow/setting-up-billboards-in-virtual-camera-compounds/#placing-the-billboard 

If your issue is that the billboard rotates to face the camera, this is because the Look at Camera parameter is not set to "Off." You can find more information about this setting here: https://aximmetry.com/learn/virtual-production-workflow/green-screen-production/virtual-camera-workflow/setting-up-billboards-in-virtual-camera-compounds/#look-at-camera 

Warmest regards,