Once you have activated your Firefly account, you can download the free Firefly app from the App Store/Google Play Store.
Search for Firefly for Parents
The school code to enter is FRIERNBARNET
If you have trouble signing in on an Apple/iOS Device you may have to
change the Date format on your phone from 12 hour to 24 hour format. In settings go to: General > Date & Time > Enable 24-Hour Time. Then try logging back in to the app.
For help with using Firefly, please see this guide