Trying to add TP-Link AX6000 as a new router on top of ARRIS GROUP, INC. TG3482G

Hi,

Currently, I am renting the ARRIS GROUP, INC. TG3482G acts as a modem/router.  I am experiment to add the latest/greatest router using TP-Link AX6000.

The first step is to replace the "router" function of this renal one.

I connected the two devices via the Ethernet cable and the TP-Link device LED showed "blue" which indicates in connection. From the 10.0.0.1 admin page, it also showed this device is connected.

However, I have trouble to get onto the admin page of this TP-Link, either through its  HTTP://192.168.0.1 or the DHCP IP.

I read from somewhere that I need to "enable" the "bridge mode". 

So I went ahead to enable it. Then I got booted out of internet access. I had to call support to remotely "diable" it to get back.

This was the warning I got

"Enabling Bridge Mode will disable the Wi-Fi router functionality of your Xfinity Gateway and turn off your existing private Wi-Fi network. If you have xFi Pods, the Gateway cannot be in bridge mode since the Pods require using the Xfinity Gateway as your WiFi router. In addition, you will not be able to access the xFi experience to manage your Pods or any other xFi settings. Are you sure you want to continue?"

I felt I am in a chicken-egg situation. 

Any suggestions on how to get this 3rd part router recognized by the local network?