@Geffers 

Usually, the DNS under WAN is obtaining from ISP automatically, with the DHCP settings, the router will provide an IP address, Default Gateway, and DNS to the clients, the DNS there is the router's LAN IP address by default. The DNS under LAN settings is the same as DHCP.

Did you set up the router already? Do you have internet now?

Please feel free to let us know if you need any further help.

@Stella.Q 

Yes, it is all working fine but still quite fathom why the DNS option is shown in three places.  Understand the internet provider being the default but if this is physically changed by the user then really just one setting needed.  This over complicates things.

Geoff lane