I'm going to put Ubuntu on my thumb drive. It's a rather large drive, so I might as well make use of the extra space.

Do I format it to FAT? Never done this before. Also, how do I enable it when I boot up? Do I have to make my computer to boot from the USB drive first in the BIOS settings or is there an easier way to do it (like clicking on an icon inside the USB virtual drive on the desktop).