UBUNTU 20.04, M15 R3, how to boot into Safe Mode?

I managed to mess up the Ubuntu NVIDIA drivers, so the M15 boots up to a black screen after the logo screens.  I read that you can hold the SHIFT key, or the press the Escape key to get to a Boot to Safe Mode screen, but all I can do is get to a GRUB screen, where there is more difficulty in getting to Safe Mode (still haven't figured out the steps). 

Anyway, is there some OTHER button I need to hold down to get to the Safe Mode menu option?