I think you are misunderstanding hang the 9, what he is saying is, you take that "fulll" windows 10 iso you downloaded.
Put it either on a dvd or use a flash drive at 8GB, then you use this tool.
http://filehippo.com/download_windows_usb_dvd_download_tool/
Once the iso is loaded onto which ever source you like, reboot the computer it in your usb or dvd drive.
Let the windows 10 installation start up, then you choose to partition your hard drive.
Delete the partition and any others, merge them into one, then you tell w10 installation "create" a new partition.
Set the size of it or in your case just leave it at default, hit begin and if all goes well it will be done in 1 hour.
http://www.expertreviews.co.uk/software/operating-systems/1401617/how-to-clean-install-windows-10-and-create-boot-media
Look at this website make sure you read the bottom so you understand what I am explaining.
On a side note if I could smack which over stupid microsoft programmers for including the reset pc function into w8 and w10 I would do so.
It causes nothing but problems for people in the long run that don't fully understand how it works.