When powered on my new Acer Desktop, I had an EFI Shell. Had Windows 10 on a USB Stick.
1. Plugged in the Windows 10 USB into the USB Slot.
2. Rebooted the Computer
3. fs1 was the USB Drive
4. fs1: <Press Enter>
5. Setup.exe etc will not work
6. Had to change path with "cd" and use "dir"
7. Choose appropriate CPU architecture X64 here
8. SETUP.EFI will execute and start the installation process.