I am planning to dual boot my computer with Windows 10 and Ubuntu on Legacy mode

which should I use for legacy Rufus or Universal USB installer? Or does it even matter? I had a dual boot system of ubuntu and 8.1 but I fresh installed windows 10(used rufus to create bootable usb selecting MBR not GPT) and the system boots straight to windows (no GRUB menu), so i think my ubuntu was in uefi or something so I am planning to fresh install Ubuntu as well..