From the link in comment:
If you're already using Ubuntu on a computer, you can already turn an Ubuntu ISO file into a bootable SD card. Simply click "System," then "Administration," then "USB Startup Disk Creator." You'll be presented with a Windows asking for two things: the location of the ISO file and the disk you would like to overwrite. Note that this method completely overwrites a given SD card, so be sure to do this only with an empty card (or a full one with files you don't mind losing).
So if you still have the ISO you are set to go. Otherwise download it first.
The only difference with that link: now you open dash and search for
Startup disc creator.