आप hit the "Print Screen" button on the चोटी, शीर्ष right side of your keyboard. It's to the left of "Scroll Lock" and "Pause Break"
That is basically like right-click=copying your whole screen, so आप have to paste your screencap somewhere and save it.
MS Paint works really good for that. Then आप can do what आप like with it, like save it, संपादन करे it, etc. या save it and अपलोड it to some other program.
Either use prntscrn button on your computer, the snipping tool if आप have Windows या use VLC player to screencap a video (there's a really good tutorial on this somewhere in livejournal).
