This is not a stand alone app. Theme require Kustom Live Wallpaper Maker PRO application What you need: Kustom PRO. Compatible launcher that supported by KLWP How to install: Download Material Cards Theme and KLWP PRO application. Open your KLWP app, choose menu icon on top left, then load preset.
Use the opportunity to get the setup package of Material Cards Theme for KLWP 1.2 for free and take a look at users' reviews on Droid Informer. The app is designed for Android 4.4 and above. It's safe to download this application. 21MaRcO12 is the official developer of Material Cards Theme for KLWP which can be found in the Personalization category.