To clean install Windows 10 operating system, you need to create a bootable USB drive using the Media Creation Tool provided by the Microsoft team. Then you need to make sure that the USB drive is selected as the first boot priority in the BIOS settings.
Now, you need to insert the USB drive into the system and power it on.
1. Select the language for OS upon booting
2. Then click on the Giant Install Now button from the installer and enter the activation details in the next step.
3. Enter the keys you purchased from the official store or bought from a nearby store.
4. Accept the terms and conditions and then select the Custom installation type.
5. You can wipe out all the data present on the hard drive while performing the Custom installation type and perform a clean install.
6. Now, you have to follow the on-screen instructions and wait for few minutes for Windows 10 to install.
Help ful blog: https://getassist.net/how-to-activate-windows-10/