More Basic IRC Information.

A: A channel is where a group of people are and in which you can speak to all of them. You could call it a chat room.

A: A server is what you must connect to first before any chatting is done. The server connects you to all the other people to chat to.

A: A client is what you use to connect to a server. This is the program that you use to type in what you want to say.