Thank you for your input!
Yes the SSID part I got down.
You are correct, I'm trying to extend the Lan if the first router.
Under LAN interface DHCP Settings, I have the option to disable, enable and relay.
To extend the LAN of the first router I'd choose relay and enter the IP of the first router, right?
But then the LAN of the RUT240 is not in the same network as Router 1.
This is where I get confused.
Which networks should I extend the WWAN, LAN and access Point to?
Is the relay option what you meant, or can broadcast relay be installed separately? If so, how? :-)