Not knowing much about this stuff, are there any clients that will 'automate' the knock for you? If so, can you make any suggestions? Or is this a matter of CLI SSH will do it, but I'm just not finding it?
It's a client/server thing, so you have to have the server running on the PC you intend to connect to (like when using ssh).
Never used it in any other way than with the CLI and not with every server I admin or use as there's other best practices also mentioned in the thread that are typically good enough without throwing in port knocking like:
Most things you can just use knocking and connect with ssh forwarding/proxy and tunnel everything through it like DB clients, IDE connections instead of having a bunch of ports open to internet. Assuming you don't kill the connection, then you can keep reusing it as a tunnel for anything else until rebooting or losing internet connection.