Use Interface – yes, otherways will not work
DHCP to no – Your router will not do DHCP, will use static IP address for your box – better then dynamic
IP Address – Static address of your box in your network (this will be address for FTP and so on), use higher numbers for last one (over 10), max. is 255
Netmask – Mask of your Nework, leave as it is
Use a gateway – yes
Gateway – IP of your modem/router, usually as default 192.168.1.1
Insert IP address of your modem/router, it will do DNS
Same as LAN.
Be sure to enter correct encryption algorythm (WPA2 in my case)
and correct password, if you use one.