Using

If you haven't used IRC before...
Simply put, IRC is a chat protocol, defined by official Internet standards, and capable of stealing many hours of your life. To use IRC, you must connect to a server, and then join a channel (equivalent to a chat room).
To connect to a server, open and select Connections New Server or press F2. In the dialog box that is displayed, select a group from the leftmost drop-down box and then a server from the middle drop-down box. The port, shown on the right, will almost always be 6667. A new window will be displayed showing the messages sent by the server to the client. When these messages have finished scrolling past, you want to choose your channel. To display a list of available channels, type /list. To join a channel, type: /join #channelname. To leave a channel, just type /part.
That's the basics, for more detailed information, read on...

Basics

Servers
allows you to connect to an arbitrary number of servers. To connect to a server, select Connections New Server or press F2.The Connection Dialog appears, and you can select a Group, then a Server, and also a Port to connect to.
Just click Connect when you're done, and a new window for the server is displayed. You can keep track of the servers you're connected to in the Server Control window.

Channels
You can connect to channels with the normal /join, by selecting Connections Join Channel or by pressing F3.
Channels you are connected to are shown in the Server Control window under the server to which the they belong. To leave a channel, you can /part, select Channel Close or press W.

Channel Options
The Channel menu, available in any channel window, contains some useful options:
T Ticker Mode 	 Displays the channel like a stock or a news ticker. Note that this mode does not allow you to enter text into the channel. To exit Ticker Mode, right click the ticker, and select Hide....
S Save to Logfile... 	 Saves the contents of the channel to a file.
A Time Stamp 	 Prepends each thing said in the channel with the time it was said, in the form HH:MM:SS

Users
In a channel, the user list is displayed along the right hand side. Right-clicking a nick in that list gives you some options, most of which are self-explanatory:
Refresh Nicks 	 Sends a message to the server to request the list of users in the channel.
Follow 	 Follows the user into whatever channels he goes to.
unFollow 	 Stops following the user.
Whois 	 Sends a CTCP whois query to the user, which provides information about the user, such as his hostname and what server he is connected to.
Ping 	 Sends a CTCP Ping to the user, to determine his echo time.
Version 	 Sends a CTCP Version to the user, to determine what software he is using.
Abuse 	 Abuses the user in one of various amusing ways.
The following commands are only available if you are an operator on the channel:
Kick 	 Kicks the user off the channel.
Ban 	 Bans the user from joining the channel.
unBan 	 Removes the ban on the user joining the channel.
Op 	 Gives the user operator privileges.
DeOp 	 Removes operator privileges from the user.