Press and hold the Power button and the Volume Down button at the same time
Release both buttons when the screenshot is taken
If needed, swipe your palm across the screen to capture (Palm swipe to capture)
If needed, use the Screenshot toolbar: press and hold the Power button, then tap Screenshot
If needed, use Assistant menu: enable it, then use Screenshot from the menu
Find your screenshot in Gallery or Photos under Screenshots, or in the Photos app’s Albums section