Samsung Galaxy S21 SG User Manual page 15

Getting started
Lock or unlock your device
Use your device's screen lock features to secure your device. By default, the device
locks automatically when the screen times out. For more information about screen
locks, see Lock screen and
Devices and software are constantly evolving — the illustrations you see here are for reference only.
security.
15
Side key
Press to lock.
Press to turn on the
screen, and then
swipe the screen to
unlock it.