How do I take a screenshot?

press

= In most Linux desktop environments (like KDE Plasma, Gnome, XFCE) this either takes a screenshot or starts a program for taking screenshots.

Where can I find that key?

Look for this group of keys at the upper right of your keyboard. Note: Print Screen (PrtScn) might have been abbreviated differently on your keyboard.

How do I make a screenshot of a single window?

Hold down 

and press