Some Internet Service Providers (ISPs) require you to keep your existing WiFi network such as Verizon FIOS. In this case follow the steps here to connect your Portal to the Internet.
You may be able to save on your monthly bill by replacing your existing WiFi network with Portal. Please contact your ISP to disable the router function in your providers box. In this case your box becomes a modem and you can follow instructions on connecting your Portal here.