How to setup Trillian
This guide assumes that you already use Pidgin for instant messaging.
In Trillian's main window,
Click the "Trillian" drop down menu and choose "Trillian preferences".
The preferences window should popup,
As the IRC plugin is not loaded by default, you will need to first choose "Plugins".
Look for the IRC plugin,
enable the IRC plugin.
Now choose the "Identites & Connections" option from the left menu pane,
Click add a new connection, and choose "IRC".
Multiple fields should now popup, waiting to be filled,
Use the screenshot above for reference on what to fill out. Obviously replacing "Nickname" with you preferred nickname and "A name" with a name you would like to use.
After doing so, choose "Connect",
It should have connected succesfully, close the window.
To join a channel, choose the "IRC connection"'s status icon from the main Trillian window,
Now go down to "Join a Channel..."
Enter a IRC channel name you wish to join
You should now be on the channel!