Can you help me?

the printscreen button.

usually above the Arqueiro keys.

Just like what @XxKeithHarkinxX said. But if you're using a laptop, press the function key (fn) + print screen (prt sc). Then go to paint and press Ctrl + V (or right click on rato then select paste) and you'll have your screen boné, cap ready. That should do the trick. :D