Like you said remote_repo_url
is indeed the IP of the server, and yes it needs to be added on each PC, but it's easier to understand if you create the server first then ask each to clone it.
There's several ways to connect to the server, you can use ssh, http, or even a network drive, each has it's pros and cons. You can refer to the documentation about protocols and how to connect to the server
You can check the rest of chapter 4 for more detailed information, as it's talking about how to set up your own server