To test that you’ve successfully integrated MixCast into your project, you should configure your own MixCast setup (don’t worry if you don’t have a physical setup for background removal, output quality isn’t an issue) and then run your application, either in-editor in VR Mode or as a standalone VR build.
By default, MixCast is configured (after setup) to run automatically, so simply running your application should cause MixCast to begin displaying to the desktop. If you don’t have MixCast already running (icon visible in the system tray), start it from the Start Menu entry “MixCast/Run MixCast“.

Note: If running your project in the Unreal Engine Editor with MixCast, it’s recommended to disable CPU performance throttling for consistent results. To apply this setting, open the Editor Preferences window, select the General > Performance section, and uncheck the toggle labelled Use less CPU when in Background