Since your Router only has one WAN Port, we need to unplug your Internet Provider's Modem and Plug in the Hotspot Bridge instead.
Identify which port your ISP Modem is connected to and unplug that cable from the Router.
This port is typically labeled WAN, Modem, or ETH 1
Plug your Cellular Bridge into the port your just disconnected the ISP Modem from using the pre-attached orange ethernet cable.