Install the app from Google Play OR using the APK file above.
Start the app.
It will ask for GPS (Location) permissions, this is normal:
Bluetooth Low Energy (BLE), specifically the active scan for devices could be used to locate the phone, for example inside a mall. For this reason, it’s in this permission category. Don’t fear, we don’t use GPS at all!
The rest should be pretty self-explanatory, just play around with it!