PORTS AND NETWORK
The CrystalSky monitor’s HDMI port allows up to 4K video to be output to FPV goggles and other display devices. Built-in dual band Wi-Fi means it can connect to Wi-Fi networks and Wi-Fi hotspots from mobile devices, and it is also compatible with 4G dongles and USB storage through its USB-A port.
From what I read the connection is between your goggles and the CS 's HDMI port, in other words the video cable HDMI out port on CS to the HDMI in port on the goggles...
Hope that helps