[Gimp-user] How to highlight regions of an image

[David Karr <davidmichaelkarr gmail com>]

(Hopefully this isn't a duplicate.  I tried to post this a few minutes ago
a different way, and I think it failed.)

I am a gimp newbie. I don't use it often enough. I'm trying to do something
that I'm certain many people have asked about in the past, but I can't find
this described in a current FAQ.

I found the current page: https://gimplearn.net/viewtopic.php?t=49 , but it
doesn't appear to be up to date with the latest gimp version (which I
installed a few minutes ago).  For instance, after copying the foreground
color onto the selection, it talks about setting a "Multiply" layers mode.
I don't see anything like that in the current interface.

What is the current guidance for doing something simple like this?