This is not the preferred streaming method on a New 3DS, as ntr-hr has notably higher performance. If you have a New 3DS, you will likely want to follow the base page instead.
Your console's notification LED should turn green, and its top screen should now be streamed to your computer
You will likely experience an average of 3 FPS with this method if you have an Old 3DS. This low framerate is normal and cannot be improved, as Old 3DS models have weak hardware
To open a game correctly, do not immediately close HorizonM Loader - instead, press the HOME button, select a game to open, and only then press A when asked to close the loader