Explanation: Upon physically connecting the router (typically via an Ethernet cable from a computer to a LAN port on the router), the next crucial step is to access its configuration interface. This is universally achieved by opening a web browser and entering the router's default IP address (often 192.168.1.1 or 192.168.0.1) into the address bar. This directs your browser to the router's internal web server, where you will be prompted for a username and password to log in. From this administrative interface, amateur radio operators can configure vital network settings such as Wi-Fi credentials (SSID and password), internet connection parameters, and critically, set up port forwarding. Port forwarding is essential for many modern amateur radio applications, enabling remote control of transceivers or facilitating specific digital mode operations by allowing external connections to reach equipment within the shack's network. Option A is incorrect because most modern routers are configured via a web interface, not through proprietary "setup software" used to boot the router. Option B is incorrect as you cannot access the internet through a router that hasn't been configured yet. Option D is incorrect; the router typically assigns IP addresses automatically via DHCP, making manual entry for "all stations" an advanced and usually unnecessary initial step.