To set it up:
1. Go to Settings > Display > Advanced > Lock screen display.
2.
Turn Show lockdown option on .
To use it:
1. Touch & hold the Power button.
2. Touch Lockdown.
Your fingerprint sensor and automatic unlock settings are disabled and notifications won’t be displayed on your
lock screen.
3. To exit Lockdown, unlock your phone with your PIN, pattern, or password.
Other settings : Display 152