The downloads are from here. Select the Englisgh 64-bit iso file and save to where you can easily find it. It will take 3.3 GB space on your hard drive. Once done you will need an iso burning software which will burn it to a DVD. either a DVD-R or a DVD+R will work. Don't think a DVD-RW will work in this instance.
Take note of the product key as you will need it when you install Win 8 using the DVD that you have previously burnt. Hope that helps.