You need to go into network setup (gx developer or IEC) & configure either melsec, tcpip or udp links.
set the required parameters in the hardware setup, download the hardware & power off & on to cold boot.
It will depend on what you are going to use to chat to it what protocol & setup you use.
A tip if you are using kepware, then it don't like tcpip use udp, well on the kepware side, I found that you can have anything in the ethernet card & it still talks.