Before you start, you can refer to the Video first:
If your router is a new UI, please refer How do I install TP-Link Archer router to work with a Cable Modem (new logo)?
Note: This article is not relevant to you if you have any of the following conditions.
1. Unplug your modem, and remove the backup battery if it has one.
2. Connect the powered-off modem to the router’s Internet port with an Ethernet cable.
3. Power on the modem, and then wait about 2 minutes for it to restart.
4. Connect the power adapter to the router and turn it on.
5. Connect your computer to the router.
6. Check for the LEDs to confirm the hardware connection, then refer to the following step to set up.
Note: If the 2.4 GHz LED and 5 GHz LED are off, press and hold the WPS/Wi-Fi button on the back for more than 2 seconds. Both the LEDs should turn solid.
Note: Please make sure you are able to access internet with a direct connection from the main computer to your cable modem. If the direct connection doesn't work, please contact your Internet Service Provider.
Log into the router’s web-based utility
Configure WAN Connection Type
After log into the router, click Network > WAN on the menu:
Select Dynamic IP as the WAN Connection Type on the right of the web page, shown as below. Then click Save button.
Wait for a few minutes and check the WAN part on the Status page, if it shows any IP address (similar as below), that means the connection between the Router and the Modem is established. If there is no WAN IP address, please move to Step 4
Click Network->MAC Clone, Click Clone MAC Address, then click Save.
If there is still no wan IP address, please restart your cable modem, wait for about 10 seconds, and then restart your router. After the restarting process, you should get WAN IP address and Internet access.
Note: Some cable modem has a back-up battery inside. To completely restart the cable modem, please take the battery out, and then unplug the power supply.