the ‘print screen’ button.
Hit that and then just paste into potatoshop.
apple/shift/3 wil allow you to select an area to take a screenshot of.
apple/shift/3 does a grab of the desktop,
apple/shift/4 followed by selecting the area you want will grab the selected area.
but I don’t know how to do it on a PC either
Press the “Print Screen” button (usually close to the Insert and Pause/Break buttons on the keyboard) – then Paste in Microsoft Paint/Lightroom/Photoshop or whatever else you use.