The ISO file is too large to fit on a CD. You will need to either burn it to a DVD, or write it to a USB thumb drive of sufficient capacity.
The instrucitons for actually burning an image to a DVD or USB thumb drive will vary, and will also depend on the operating system you are using.
Please see one of the following guides for more information:
Burning to DVD: https://help.ubuntu.com/community/BurningIsoHowto
Using USB stick: https://help.ubuntu.com/community/Installation/FromUSBStick
The first option, burning to DVD, will be much easier to follow especially if you're on Windows, and I would recommend it unless you don't have the ability to burn DVDs.