Passing DHCP to Airport Extreme

I have a router/gateway that is set up to do DHCP by default. However it appears that in order for the Airport Extreme to do "guest networking", a very important feature for me and the reason I bought it, I have to allow the Airport Extreme to do DHCP. Is this correct?

I tried to turn off DHCP on my router, but everything got screwy. Nothing would connect to anything. This makes sense because nothing was assigning IP addresses at that point, but I don't understand it enough to solve the problem. The Airport was asking for a DNS server too. How can I set this up correctly?

Please help. Thanks!

I got the DHCP disabled and the Airport set up correctly. It was a matter of getting the IPs manually entered correctly. However, guest networking still does not work because the modem provided by the cable company translates the IP with NAT and does not pass a WAN IP.