All StudioLive scene, preset, and backups are located in the following directory (Classic Mixers will have just StudioLive folder):
Documents > Presonus > StudioLive AI > Library > Presets
In there you will see the following directories:
The Backup file can be renamed as a .ZIP file if you want to open the backup and extract specific scenes and place them in the scene folder. If your backup/scenes are not there, then they were saved to another location or device.