Configuring the right DNS address, quad wan router (20-05-18)

Was configuring replacing a dual wan router to a quad wan router because customer needed to have more than 2 public ip forwarded. I think you can use the one to one nat. But I am still not sure about configuring that. So I was using the normal way of pluging 4 lan cables from the first router to the second router which is managing the network. I copied the settings but I seem to have missed out on the DNS address which made me waste a lot of time testing to see what was the problem. Also DHCP relay is said to work if your DHCP is on another subnet DO NOT ON it if you are on the same subnet. I tried to on it on the same subnet and it gave me tons of trouble. In the end. Managed to configure the router to a working condition after correcting the DNS address and also disabling the DHCP server and not doing the DHCP relay