First congratulations for your job

I installed on my pc MX14 with unetbootin and mx.iso. I lost access to my first distro (M12) to launch grub and it's more complex than grub 1.
can you help me and explain the grub file to modify the menu to add M12

thanks

Did you try to use the grub-customizer in MX14?

Oups ! so easy ! thanks