You can backup your save by logging into Facebook (iOS and Android) or Google Play (Android only). F1 Manager has multiple pop-up screens throughout the game to remind you of this. If you have connected to Facebook please reconnect to FB in game to load your progress by clicking the profile icon on the main screen or reinstall the game and choose to connect to FB on the login screen.
If you are using Android:
1. Sign into the Google Play Games app on your phone
2. Go to Settings
3. Make sure Sign me into games automatically is checked
4. Start F1 Manager to load your progress
If you are intending to transfer your progress from one Device to another we highly recommend you save to both Facebook and Google Play to ensure that your save is carried across and retrievable, there is currently no way to transfer your save without Facebook or Google Play. You can also login to Facebook to transfer progress across to Android and iOS and back.