- Download macOS from somewhere. Easiest way is to use an existing mac to download it from the App Store.
- Use Unibeast or terminal installer to generate a usb installer
- Download Clover EFI Bootloader and run it against the USB you generated in step 2. This will configure the EFI partition on the USB and fix anything bad Unibeast might do. I recommend selecting the UEFI options and the RC scripts on target volume options.