So I downloaded a Windows 10 Disk ISO. I tried installing it to a partition on another hard drive and it worked, so I know the ISO is valid. 
Second, from that other hard drive, I ran gparted and got my primary hard drive split in two, with the first partition being the one I'm using now.
What I now need to do is get that ISO onto that second partition in such a way as I can launch the windows installer and install windows on that partition. 
I tried formatting the second partition as NFTS and just copying the ISO's files onto it as I had done before when testing the ISO. I then ran the update-grub command. It found a windows **7** option and a windows recovery option. When I restarted and selected either option the select screen would simply freeze for a bit. After pressing a key when it was frozen the select screen would disappear and all I saw were a bunch of randomly coloured lines that just stayed there.
I just tried running update-grub again and now there's only one entry in my grub.cfg file:
    ### BEGIN /etc/grub.d/30_os-prober ###
    menuentry 'Windows Recovery Environment (loader) (on /dev/sda2)' --class windows --class os $menuentry_id_option 'osprober-chain-00C7FFBD4C4600A8' {
    	insmod part_msdos
    	insmod ntfs
    	set root='hd0,msdos2'
    	if [ x$feature_platform_search_hint = xy ]; then
    	  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos2 --hint-efi=hd0,msdos2 --hint-baremetal=ahci0,msdos2  00C7FFBD4C4600A8
    	else
    	  search --no-floppy --fs-uuid --set=root 00C7FFBD4C4600A8
    	fi
    	parttool ${root} hidden-
    	drivemap -s (hd0) ${root}
	    chainloader +1
    }
    set timeout_style=menu    
    if [ "${timeout}" = 0 ]; then
      set timeout=10
    fi
    ### END /etc/grub.d/30_os-prober ###
I feel like if I set the "boot" flag for the partition I could get it to work, but then I might end up losing the ability to boot back into my primary Ubuntu partition. 
tl;dr If I want to boot to a partition with a Windows 10 ISO burned to it, what should my grub.cfg entry look like?