After the registration process, download the APK here and save into usb pen.
Follow step by step this guide for the installation.
Launch WallSign application and after few seconds you should see an activation phrase.
That phrase must be placed on the WallSign dashboard: login to app.wallsign.eu, go to the Player section and press Add button, selecting WallSign.
N.B.Remember to set the right time zone from the Philips display settings.