This is how i did my clean install. Upgrade from Windows 8.1 to 10. After upgrade completed, extract the product key from upgraded windows 10 (there are some free tools to do this, i forgot mine as i tried a few tools before i perform clean install).

Create a bootable USB by using the Windows 10 Media Creation Tool (https://www.microsoft.com/en-us/software-download/windows10). U will need a minimum 4GB USB flash drive depend on the Windows version u download.

Boot up using USB, format and clean install with the extracted product key.

So, you might wanna swap back old HDD, extract the product key and then swap back to SSD and perform clean install again.