Configure a TP-LINK router as a bridge / access point / wifi extender with a WiFi connection (not cable-connected to the main Internet router)

1. Do not touch the main router. There is nothing to configure there.

2. Cable-connect your TP-LINK router (Ethernet) to your computer and go to it's UI by typing the IP, typically 192.168.1.1 or 192.168.0.1

3. Go to Network -> LAN Settings. Change IP address to an IP which is in the LAN segment from your main router, but not in its DHCP range. E.g. if the main router / default Gateway IP is 192.168.1.1 and the DHCP range is 192.168.1.100 - 192.168.1.199 then any IP between 192.168.1.2-192.168.1.99 will do.

4. Disable DHCP server.

5. Click SAVE

6. The router is supposed to reboot. Go to DHCP server and double verify that it is disabled.

7. Go to Wireless -> Basic Settings (or whatever it is called in your model) and switch on "enable WDS". You might need to define specific channel on main router, e.g. 11 and match it on the bridging router by selecting Channel = 11. The same is correct for the Channel Width. Name your WiFi in the way you want, e.g. "my_home_NW_EXT"

8. Hit Scan / Survey button to get the list of available WiFi networks. Select the network broadcasted by your main router and hit "Connect". Enter the password for that network as defined in the main router. Note that it is NOT the password to access the new WiFi network you are defining: "my_home_NW_EXT".

9. GO to Wireless -> Wireless Security where you define the security for your new network "my_home_NW_EXT" and define the password you will use while accessing thi snetwork it could be the same password as for teh bridged network or another one.

10. Reboot the bridged router. Cross your fingers, it should work now.