Basic IRC command usage guide:
/query nick - start one-to-one conversation with nick
/me message - write a nice message/notice to channel
/msg somebody message - send single message to nick/channel
/join channel - joins channel
/leave channel - leaves channel
/quit [message] - quit irc with optional message
/nick nick - change your nick to new one
/topic new topic - change channel topic (you need to be operator!)