Like stated question this is a download and backup disc for windows 8. I am going to be installing a new motherboard into my computer and I've never done so before so if I put in the backup disk would it start loading windows for install off the backup disc or would I need another new retail copy of windows.
You linked me to an "UPGRADE" copy of Windows, not a full copy. An upgrade copy requires XP, Vista or Windows 7 to be already installed. While it MAY also work without a previous installation if you have the appropriate XP/Vista/7 Install disc that is unused or registered to that motherboard, by your description it appears you simply have a new motherboard and an Upgrade copy of W8.
Upgrade copies of Windows require a previous version of Windows to upgrade from.