Change from dsl to cable

First you will have to log into the router (typically 192.168.1.1 in a web browser)  On the main screen you should see Network Configuration, just drop the menu down and choose DHCP. Save the Settings and reboot the router and new modem simultaneously.
If you don't have any settings saved into the router, you could also just hold the reset button on the back for 10 seconds, this will default back to original settings.
Good Luck!

simplest way to bring the router back to dhcp and to intiate connection with modem is to reset router
connect the modem and the router >> at the back of router you would have a small button tat says reset press and keep it pressed for 30 sec
tat shld do it