You just unboxed a SOHO wireless router for a home office on Willowbrook Lane. It is at factory defaults. Bring it online from scratch: get the WAN link up from the ISP, stand up a secured Wi-Fi network, define the home LAN and hand out addresses with the router's DHCP, and replace the default admin password.
Work through the four admin tabs in any order. The checklist updates as each piece comes up; the router console tells you when something is wrong and how to fix it.
The fiber/cable line plugs into the WAN port. Most ISPs hand the router an address automatically.
This router ships with the factory login admin / admin. Replace the password before anything else.