I've not used mIRC in about a year or more - but I'm starting to use it again. I can't remember what it was I had to do to authenticate I remember you had to type something into the client which sent you an email and then you signed up and so on.

Anyone be kind enough to remind me what it was?

While most networks that have nick and channel services use a (fairly) standard command sequence, Quakenet (which you specified) has it's own.

The best place to get specific help for commands to be used on Quakenet is in their help channel. I believe that the channel is called #help