You dont ISO Format it to the disc. The download will be in ISO format. You will burn the ISO which will extract the files and burn those to disc. A ISO is a Image of a disc. Like a full Vista DVD that you download from Microsoft is in ISO format.
ISO image - Wikipedia, the free encyclopedia
After you burn the ISO to a CD then yes it should just boo up and give you the menus for GParted. Get into the software and format the drive.