

This time you will need to erase all partitions to remove macOS before installing.Boot Camp requires a Mac with an Intel processor.

Once you have booted to a working Windows 10, you can use the Windows 10 flash drive installer to reinstall Windows 10. One possible procedure which might work with your Mac is given as the answer to the question How to install Windows 10 into a 2011 iMac without using the Boot Camp Assistant, an optical (DVD) drive or third party tools?. However, you would be better off first installing Windows 10 for a dual boot with macOS.

If you do not want or need macOS installed on your Mac, then you can just have Windows 10 installed. See the question WDF VIOLATION Blue Screen after Upgrading Mac to Windows Update (1903) Edition.
