difficulty using the 'Find Cursor' feature on MX-21.3
 

I am running MX Linux on an elderly Lenovo Thinkpad with 4 G of RAM.
I find the ability to make the cursor flash sometimes convenient (indeed, sometimes I wish it would flash more brightly!).

Going Menu>Settings>Accessibility>Mouse shows Find Cursor followed by a statement that begins "Bind a keyboard shortcut". Unfortunately I have found no explanation how to do this.
I'll be grateful for suggestions!

You do it via "Application Shortcuts". See this thread @XFCE forum.

And there it is! Control+Alt+M does it (which seems a bit complicated, but why complain).
There I was saying I'd like a brighter flash—this is so bright I jumped!