How can I implement an OC bootloader on a hard drive and add oc to the list on NASM and C?

Question

C++ / C#

There is a test code in C (like a kernel) and a bootloader on NASM, but I want to test on VirtualBox, I need an installer (from scratch) on NASM and C to load the kernel and bootloader, also add to automatically load OC.

Answer 1

It depends on what hardware you are making the OS for.
If for the old one you may have to use NASM or some other assembler,
and if for the new one, then UEFI is the best way.