How can I turn off the router in my modem and use my own?

Episode 1453 (1:08:39)

Dan from Corona, CA
TP-Link Archer C7

Dan has AT&T and a new TP-Link router. Can he use his own with the AT&T DSL modem that has a router built-in? Leo says yes. He can turn off the AT&T's router radios and network address translation. He could try putting it into bridge mode. He'll have to open up the browser IP address and look for a place that will enable him to turn off the router altogether. He'll also have to disable DHCP. If he can't do that, then he can put the TP-Link into bridge mode and it will just pass the signal along. He should also look for a passthrough mode. Someone from the chatroom says he gave up on AT&T and went with another ISP, but Leo says that's a drastic option.