Connect an ethernet cable from your computer to the SPA3102’s ethernet socket.
In a browser go to 192.168.1.1 you should see the SPA3102’s web interface, if not check your computer is set to use DHCP to get its ip address.
In Router – WAN Setup change Connection Type to Static IP. Change the Static IP, Netmask, Gateway and Primary DNS to the correct values. For instance, on my networks all computers are 192.168.0.something and the broadband router is 192.168.0.1, so I use 192.168.0.7 as my Static IP, 255.255.255.0 as the netmask, 192.168.0.1 as both the gateway and primary DNS.