First of course the PLC must comprise an Ethernet card.
In the ladder code add the function TCP/IP card init after a direct contact of SB2 and configure the IP address, Subnet mask and default gateway according to your network settings.
Add the function PLC name after TCP/IP card init and configure your PLC name.
Download the application and reboot the PLC.
Then using VisiLogic, Remote Access, or any other Unitronics software.
You can access the controller via the IP address, PLC name and the port 20256 or 20257 if you did not change the sockets settings.
Please note that you can also configure each one of the sockets to other port number and TCP slave and later use this port number for connection.