How-to
It is not really our job to provide comprehensive guidelines to IRC as we expect most of our users to be already somewhat experienced in this area, plus you can find all the related information elsewhere should you take it seriously. However, even to this day there are long-term and lazy IRC users who either don't know or keep forgetting how to perform rather trivial operations such as registering their nicknames and creating and managing channels. This page should serve as a reminder for all these things rather than a full-scale IRC guide.
What you should know is that most operations on IRC are performed using NickServ or ChanServ, which are the two principal and self-speaking units of the IRC services application, which is something like a bot. One serves nicks, the other one channels, accordingly. To do either one the traditional way you do something like /msg NickServ parameters or /msg ChanServ parameters, where /msg is literally sending a private message to these entities to receive a response in a form of a particular action. However, there is a simplified approach to it, which reduces the above to just /ns and /cs, which is what we are going to use from this point onward.
Registering a nickname and identifying with the services
Pick a desired nickname using /nick your_nickname and then do /ns REGISTER your_password your_email
Upon that you will receive an email with a confirmation - a randomly generated character string, which you can just paste in the text input field of your client. Identification happens automagically, too. However, next time you connect to the network you will have to log in yourself. To do that type /ns IDENTIFY your_password. If you forgot your password you can always do /ns RESETPASS your_nick your_email to have a new password emailed to you.
For a full list of NickServ commands type /ns HELP or to get help for a specific command from that list type /ns HELP command.
Registering and maintaining a channel
To register a channel you must be identified. Join a desired a channel using /join channel_name an then do /cs REGISTER channel_name channel_description