Connecting to ZNC
You connect to znc using any ordinary irc client. Point your IRC client toplus.IRC4Fun.net using (ssl) port 7000.
You may configure your znc account via irc commands. To do so, message "*status" for help. Example:
/msg *status help
Connecting to Multiple Networks
Authenticate withzncuser/zncnetwork:password
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.username/networkname
Create another network, name it whatever you like (for example "freenode"), and add the irc server address to the network.
Then authenticate with a separate irc connection to zncuser/libera.chat:yourpassword