Your settings and data are restored from iCloud when you start the TomTom app after you have restored your iOS device, changed to a new iOS device, or removed then installed your TomTom app.
You see the message An iCloud backup was found, do you want to restore your settings?. Tap Yes to restore your settings and data.
If the iCloud backup could not be restored (because contact with your network was lost, for example), check your network settings and try again.