It sounds like you’re looking for the user manual for the (often a broadband router or gateway provided by ISPs like HughesNet or other satellite/wireless providers).
By midnight, Leo had reset the DNS settings, the light turned green, and his Wi-Fi was back. He printed the manual’s troubleshooting section and taped it to the wall beside the router.
He found the router in a dusty corner of his closet, where the installer had left it two years ago. No quick-start guide. No CD. Just the box with a faded label: Sagemcom CX2000-9 .