Assuming it’s the same process as VW, you need to go into the ‘System Setup’ menu. You’ll see a ‘Factory Settings’ item. select it and there should be an option to restore factory settings.
I did this in my previous VW when I sold it, and it deleted all my personal settings - radio presets, phone book, removed the Bluetooth connection to my phone.
Edit; it’s covered in your infotainment system manual;
