Sorry if I offended. It wasn’t my intention. If you feel you are ready for it then things like this make an excellent learning experience.
However, please go into it knowing what you are contemplating doing is not easy. Fundamentally, what you need to do is:
- Update your system.
- Make a backup.
- Use a tool to convert your disk to GPT. After doing this it will no longer boot.
- Boot off a Linux ISO.
- Resize and relocate your partitions to make room for an EFI partition.
- Create an EFI partition manually with the appropriate flags.
- Format the EFI partition.
- Mount your root partition.
- create a boot/efi partition in that mounted partition.
- Mount your EFI partition at boot/efi.
- Chroot into that mounted system.
- Re-install grub for efi.
- Modify
/etc/fstabwith the correct UUIDs for your root and swap partitions. - Add an entry for your EFI partition.
- Exit the chroot.
- Unmount all the partitions.
- Boot into your BIOS and select the efi as your default boot device. (This is only needed because it is probably currently set to legacy boot from a specific partition)
- Hope everything works, if not, troubleshoot from there.
Please note, I haven’t tried the above, that is just how I would think through it. It is possible I missed steps.
I don’t think you will find a perfect tutorial where you can copy/paste commands. It will probably take some exploration and interpretation.