Well, there are sveral ways to do it. On my keyboard to take a screen shot, it's "shift key and at same time Prt Scr" that puts the image to the clipboard. (It could be other keys, or just a print screen key. )

Then you open an image editor, Paint is easy and on most PC's. The "ctrl and V" will paste from the clipbboard. Select the area you want and crop, I use a box with fill to cover personal info (names & pix of opps)