To connect in mirc:

Open mIRC.
Go to File > Options.
Select Connect in the left column.

Since it's your first time, you need to add the chat server manually - you don't have to do this again once it's done (unless to reset mirc or something )

To do this, click the Add button on the right.
Give it some description you want
Type <B>209.69.98.11</B> in the IRC Server box. (The real name is <B>irc.ffchat.net</b> but that occasionally gives problems for some people due to DNS issues, so it's safer to use the IP address for now).
Port number should be changed to <B>6669</B> - 6667 is a different chat network on the same machine, where you won't find us lot
Group can be what you want (or left blank).
Password should be left blank.
Then click Add.

Now it's added, whatever description you gave it is what the server will appear as in the bigger dropdown box in the Connect options. Find it in the list, then before clicking connect, make sure the Full Name, Email Address and Nickname boxes underneath are filled in as you want them to be, then click Connect To Server.

You'll get another window, which will show lots of garbage as it's connecting. Once you see <B>End of /MOTD</B> (message of the day), type <B>/join #eoff</B> and it should make you join the channel