Firstly, you'll need to connect to the toribash's irc server.
iirc the command was was /server irc.toribash.com (can be wrong)
When you connect to the server, you can join any channel by using /join #channelname.
you can join multiple channels using /join #channel1,#channel2 (no spaces b/w commas)
Puting the servers and the chanels on auto-join always helps, though.