Hi I bought a Netgear WNDR3700 without realising it is not an ADSL router which i'm not allowed to return. Note the Netgear runs DD-WRT so it's not the factory firmware.

I have no idea how to make it work with my Telecom supplied Thomson TG582n ADSL router so i can get internet ...

This is what i've done:

1) plug Thomson ethernet 1 to Netgear "Internet" port - the internet light is green whatever that means

2) log into Netgear and hit Setup - Basic Setup - WAN Connection Setup - DHCP

What's the next step?