To be able to triple boot on a single hard drive connected to an Arous, Gigabyte, or MSI motherboard, you will need to boot Clover EFI from a USB Flash Drive. Set that USB Drive with the Clover EFI bootloader as first in your BIOS. This ensures GRUB and the Windows Boot Manager on the single hard drive will not be in conflict with the Clover bootloader during installation.
Triple Boot on Three Drives
To skip the USB Flash Drive and prevent the bootloaders from clashing, you can install each OS on its own HDD or SSD for a total of three drives and target the macOS drive with the Clover EFI bootloader in the BIOS>
Triple Boot on Two Drives
To do this with two drives to keep a third for storage or due to limited SATA ports, install Windows (and Windows Boot manager) and then Ubuntu (and Grub) on your second drive and macOS (and Clover EFI) on your first drive and set your BIOS to boot Clover from the primary drive.
Triple Boot on One Drive
To do this on one drive due to a small factor case or laptop, install Windows in the first partition followed by Ubuntu in the second partition and macOS in the last partition and then fix the ESP during post-installation by tweaking the files in the BOOT folder. As you can see, knowing how to create an EFI Partition will come in handy for such an installation so practice on this for awhile.
Demonstration of Triple Boot
Configuring the Triple Boot