Hi Duh! Jk
To take a picture if you have windows, you need to select the window you want to take a screenshot of, then press Print Screen key and the ALT key at the same time on your keyboard (you can also just use the print screen key if you want to take all your screen in screen shot) and then you need to use paint, go in the option Edit and finally Paste and after that you need to save the picture more usually called a screenshot though ^^