access the IP address of your router to get to the router setup page.
From the main setup page, click on the Setup tab at the top, and the Network button on the left side. From there, you can turn on DHCP and set that up.
Next, click on the Inernet button on the left side, then click on Manual Internet Setup. From there, you can choose to give your router a fixed IP or let it get one from your other router, and you can also assign fixed DNS server IP addresses.
Hope this helps