Press and hold the Side key and Volume Down key together
Tap Power off on the screen
Tap Power off again to confirm
If the phone is frozen, press and hold the Side key and Volume Down key for about 10 to 15 seconds until it restarts, then power it off normally
On some Samsung phones, press and hold the Side key until the power menu appears
If needed, swipe down from the top of the screen, tap the Power icon, then tap Power off