Dual boot windows 7 and windows 10 tutorial from 04/004/2016

For some reason this won't work on my PC because when I go to http://www.microsoft.com/en-us/softwaredownload/windosw10 to create a windows 10 ISO bootable USB there is no option to create a bootable ISO image of windows 10. The only option I am allowed is to to upgrade my windows 7 to windows 10. I have a Lenovo desktop less than 2 years old. Any suggestions on what I may be doing wrong? Or is this not possible to do on my PC?
Thanks
Roger B