Im assuming your using 3.0 basic or 3.0 pro.
First box what ever you want. IE mine is "FishChat"
Second box "irc.webchat.org"
Third - Fith box I simply put the nick I use on IRC.
I marked the Connect on startup box.
I also went into the IRC connection properties and specified a series of commands to run upon connection that basicly identifies my username with my password and connects me to the IRC channel #aquariumadvice
/ns identify #PASSWORD#;/join #aquariumadvice
Where #PASSWORD# is the password you used when you registered your IRC nick. If you dont have a registered nick then you dont need that command.