To avoid major updates download from windows Microsoft provides Windows 10 build 15025 ISO files for clean installation. This ISO is for clean installation which includes all latest test builds.
Microsoft released this ISO so that software developers and DBA’s pull their socks to do early testing and improvements in their environment.
To download ISO we must require membership of Windows Insider Preview program, if you are already a member then you can download using windows update for windows.
Windows 10 build 15025 ISO (Download Link)
Use above link to download ISO, we need to choose the edition first and then click confirm tab to download the ISO.
After download we can use USB thumb drive for windows installation but first we need to make USB thumb drive bootable, there are too many tool available online to make USB pen drive bootable.
If we are upgrading from Windows 7 or Windows 8.1 then clean installation is required for Windows 10