So I just bought a Macbook pro with Lion. I was told it didn't come with a backup disk or something of that nature. I was told to purchase an 8gb thumb drive to make a backup in case something goes wrong. Does anyone know what this means and how to do it, step-by-step in complete idiot terms? I am brand new to Macs and I am having a hard time adjusting so any help and patience would be greatly appreciated. Thanks.