This is not a standalone app
In order to use this locker you need to Install the following applications:
--Kustom LockScreen (Pro Version)
https://play.google.com/store/apps/details?id=org.kustom.lockscreen.pro

You Will Get
-Elegant LockScreen
-Automatic Wallpapers (You choose the time)
-Customize with the different widgets included
-Animated music player
-Slide to find many options
-Animations and More
-Don’t miss your important Notifications

How to use:
Open the Elegance KLCK app from App Drawer and choose your favorite Kustom Lockscreen.
Kustom LockScreen will open Just Click on the save icon and you're done.
Soon Samsung Lockscreen stay tuned.

If you have questions please contact me.