Isn’t the number one problem here that you’re following a Stack Overflow post? Your system should have good documentation on how to configure networking, or some obvious sanctioned way to do it, such as a GUI widget. If your system has neither, that’s the problem. If it has one or the other and you’re using Stack Overflow anyway, that’s the problem.

Note I said “good” documentation - many Linux systems have lousy documentation and they lack an obvious, sanctioned way to do it. Again, that’s the problem.