As Gene has indicated, under Chrome and on this page the only way to activate these things with a screen reader is to use screen reader mousing controls.
By the way, and not that Gene is incorrect in any way, if you happen to have a keyboard with a "hard insert" key (as in dedicated an which only has as it's function Insert) you can use that along with the number pad slash character as well.
If you have a laptop with a full number pad you should be able to use the desktop keystrokes as he's given them. If you have a laptop without a number pad, and presuming the NVDA key is still INSERT, then the keystokes are:
Move mouse to current navigator object INS+Shift+M
Left click mouse INS+[
Brian - Windows 10 Home, 64-Bit, Version 1809, Build 17763
A great deal of intelligence can be invested in ignorance when the need for illusion is deep.
~ Saul Bellow, To Jerusalem and Back