So you run Linux, and you didn't run in any problem to troubleshoot. Great! There's still a lot of interesting stuff you might want to know about your desktop, both to quickly pinpoint the root cause of a problem if anything breaks, and to get a better grasp of what's possible to do.
When you open your Linux laptop a few things take place, but at some point the kernel will launch the first process, or PID1 0. In most modern linux desktop it's systemd
Process ID