This part of the site will give you a good description on how to connect to ZICS.
The most basic connection to the server is using telnet:
It is much better to connect to ZICS using a quality GUI tool.
The best one we recommend was compiled by one of our own members
using Winboard. (Xboard is the Unix GNU equivalent - see the
links page for software)
After you download and install the software, goto the 'Winboard.ini' file in the Winboard directory.
Edit the text file until you get to all the chess servers.
As in the picture there you see zics.org /icsport=5000
Add that to your winboard.ini file.
Save your file then run winboard.exe.
It should connect, and ask for your login name.