Follow the upstream instructions for installation.
Then, create a new config interactively by calling znc --makeconf.
Here's an example of a config for the Libera.Chat IRC network:
[ .. ] Checking for list of available modules...
[ ** ]
[ ** ] -- Global settings --
[ ** ]
[ ?? ] Listen on port (1025 to 65534): 6697
[ !! ] WARNING: Some web browsers reject ports 6667 and 6697. If you intend to
[ !! ] use ZNC's web interface, you might want to use another port.
[ ?? ] Proceed anyway? (yes/no) [yes]: yes
[ ?? ] Listen using SSL (yes/no) [no]: yes
[ ?? ] Listen using both IPv4 and IPv6 (yes/no) [yes]: yes
[ .. ] Verifying the listener...
[ ** ] Unable to locate pem file: [/var/lib/znc/.znc/znc.pem], creating it
[ .. ] Writing Pem file [/var/lib/znc/.znc/znc.pem]...
[ ** ] Enabled global modules [corecaps, webadmin]
[ ** ]
[ ** ] -- Admin user settings --
[ ** ]
[ ?? ] Username (alphanumeric): paveloom
[ ?? ] Enter password:
[ ?? ] Confirm password:
[ ?? ] Nick [paveloom]:
[ ?? ] Alternate nick [paveloom_]:
[ ?? ] Ident [paveloom]:
[ ?? ] Real name (optional): Pavel Sobolev
[ ?? ] Bind host (optional):
[ ** ] Enabled user modules [chansaver, controlpanel]
[ ** ]
[ ?? ] Set up a network? (yes/no) [yes]:
[ ** ]
[ ** ] -- Network settings --
[ ** ]
[ ?? ] Name [libera]:
[ ?? ] Server host [irc.libera.chat]:
[ ?? ] Server uses SSL? (yes/no) [yes]:
[ ?? ] Server port (1 to 65535) [6697]:
[ ?? ] Server password (probably empty):
[ ?? ] Initial channels:
[ ** ] Enabled network modules [simple_away]
[ ** ]
[ .. ] Writing config [/var/lib/znc/.znc/configs/znc.conf]...
[ ** ]
[ ** ] To connect to this ZNC you need to connect to it as your IRC server
[ ** ] using the port that you supplied. You have to supply your login info
[ ** ] as the IRC server password like this: user/network:pass.
[ ** ]
[ ** ] Try something like this in your IRC client...
[ ** ] /server <znc_server_ip> +6697 paveloom:<pass>
[ ** ]
[ ** ] To manage settings, users and networks, point your web browser to
[ ** ] https://<znc_server_ip>:6697/
[ ** ]
[ ?? ] Launch ZNC now? (yes/no) [yes]: noThen, run systemctl start znc to start ZNC as a system daemon.
Make sure the server is available from outside (this means setting up DNS and firewall). You can skip setting up an SSL endpoint for ZNC as many IRC clients accept self-signed certificates.