How to configure the Linux OS?

Answer 1

This isn't a straight-forward question to answer.

Desktop configuration is generally done in the KDE, GNOME, or XFCE (or another) desktops themselves, to set languages and themes and keyboard behaviour and monitor setting and the like.

Networking configuration may be done in a Graphical (GUI) app but it may be on the command line or by editing a text file.

Printing may be in a GUI app or in a web browser at http://localhost:631

Some distros, like OpenSuse and Mepis, have a GUI to configure mush of the system; other distros rely on the users to know how to use text editors and read the wikis at the distro websites.