Connecting to ZNC
You connect to znc using any ordinary irc client. You may configure your znc account via irc commands. You may find it a lot easier however to configure your networks and settings using the Web configuration module. In which case, you would navigate to http://znc.example.com:6667 or https://znc.example.com:6697 depending on your port/ssl configuration.
If you have multiple irc networks setup under your znc account, you may connect to a specific one directly by adding /networkname to your username like so
Some Popular IRC clients
/set user_name myusername
Or to connect to a specific network you have setup add /networkname for instance
/set user_name myusername/freenode
Now connect and supply the password
/connect znc.exmaple.com somethingheredoesntmatter "this is my password"
Or you can simply connect without a password and supply it after you've connected by running
At which stage you may enter your password by doing
/quote PASS myusername:mypassword
It doesn't matter what you put for nickname as the server will readjust to what the network is set to.