The side fingerprint scanner makes the unlock process easier, touch the Power button to instantly unlock your phone and to do this and you first need to add fingerprint that can be done by following the steps below.
1. On the Settings screen, tap Biometrics and security > Fingerprint Scanner.
3. Place your finger on the Power key. After the device detects your finger, lift it up and place it on the Power key again. Repeat this action until the fingerprint is registered. When you are finished registering your fingerprints, tap DONE.
When a fingerprint lock screen appears, tap TURN ON to use your fingerprint to unlock the screen.