This is not a stand alone app. Card_widget require KWGT PRO application
What you need:
✔ KWGT PRO App
Pro key https://play.google.com/store/apps/details?id=org.kustom.widget.pro
✔ Custom launcher like a Nova launcher (Recommended)
How to install:
✔ Download Card_widget and KWGT PRO application
✔ Long tap on your homescreen and choose Widget
✔ Choose KWGT Widget
✔ Tap on the widget and choose installed Card_widget
✔ Choose widget which you like.
If the widget is not right sized use the scaling in the KWGT option to apply correctly size.