This is a tutorial for using Apollo to stream different monitors to different Moonlight windows.
My usecase for this is streaming my multi-monitor desktop to a different multi-monitor setup within my home network. For outside networks, UPnP needs to be checked inside Network tab of the Configuration menu in the Apollo web UI. I would still recommend pairing with additional Apollo instances inside your home network for ease of use.
This tutorial assumes that you are installing Apollo to Windows.