now i will tell you how to set face unlock feature on your android phone. Face unlock feature is used to unlock your phone by your face... You must have front camera for this feature.
Since it requires a rooted android, so i'm not responsible for any damage..

step1: basic
~ download & install es file explorer on your phone.
~ open it. Go to menu<tools<root explorers and turn on it.
~ download part1 and part2 zip files attached below and extract it with es in memory card.

Part1 contains: facelock.apk , lib(folder) , addon.d(folder)
part2 contains:
vendor(folder)
step2: setting up files
~ move facelock.apk to /system/app
~ move contents of lib folder to /system/lib
~ move contents of addon.d folder to /system/addon.d
~ move contents of vendor folder to /system/vendor
(if any folder is not present in your system, you can create that)
after this, you have to set right permissions for all files otherwise it will not recognise by your system.

step3: setting permissions
to change permission with es, touch & hold on system file or folder & then more..>properties>permissions change
set permissions of files to -rw-r-r-- (see ss)