Download the apk and add it on the usb key: https://dynamicscreen-android.fra1.digitaloceanspaces.com/app-release.apk
Plug your usb key into the screen.
Go to the Menu(swipe to the top) and click on "Files":
Click on USB drive and select the app-release:
Click on "Install":
Click on "Allow":
You arrive on this screen which provides you with a code to associate your screen on Comeen Play: