Well welcome to mIRC.
So First timer to mIRC let me see if I can explain this well.

First open the "Options" under the Tools tab. On the tab Connect set your nick and an alt nick if your nick is taken

Then we need to open an window if it is not opened yet, go to the upper left corner of mIRC and open the File tab and then click on "New Window".now we have to connect to a server wich is in this case QuakeNet. In the window use the command "/server de.quakenet.org 6668" to connect to our server. Now you are connected you need to join bobs by typing the command "/join #GuardsmanBob". And now you are in his channel

If you want to you can use a simple script wich will connect you each time you start up mIRC, you will have to put this script in the remote script wich you can find under Tools "Script Editor" just edit the yournick into your nickname.

on *:START: {
  /server de.quakenet.org 6668
}

on *:CONNECT: {
  if ($network == QuakeNet) {
    /nick yournick
    ; The line below is only needed if you have an account on Q.
    .msg Q@CServe.quakenet.org AUTH username password
    ; Put any channels you'd like to join under this line.
    /join #GuardsmanBob
    }
  }

no problems man, I bet there is other people on the forum who have alot more experience with mIRC then I do and can give you better scripts and stuff ^^