To take a screenshot on your Pixel, you'll need to press two buttons at the same time: the power button and the volume-down button. Make sure you press them simultaneously, or it won't work. It's a bit like a secret handshake, but easier to remember!
The power button is usually on the right side of your phone, and the volume-down button is on the left. If you're still having trouble finding them, just check your phone's manual or look for the buttons with the volume and power symbols. Once you've found them, you're ready to take your first screenshot!
