How to highlight in a PDF document when using Preview (v 11)?

I read recent q's of the same type; while I know I can switch to Acrobat Reader to do it, I'd rather solve the problem I am having in Preview please.

When I could not figure out highlighting intuitively, myself, I opened up Help in Preview (using MacOS Monterey 12.2) and followed the directions carefully twice. See below pasted from Preview User Guide.

Highlight, underline, or strike though text

In the Preview app on your Mac, open the PDF you want to change.

Do any of the following:

Quickly highlight, underline, or strike through text: Select text, click the down arrow next to the Highlight button , then choose a highlight color, underline, or strikethrough.

Use highlight mode: Click the Highlight button (so it turns gray), click the down arrow next to the Highlight button, then choose a highlight color, underline, or strikethrough. Now, whenever you select some text, the highlighting style you chose is automatically applied to the text.

To turn off highlighting, click the highlight tool again.

Remove a highlight, an underline, or a strikethrough: Control-click the text, then choose Remove item from the shortcut menu.

-Both times, the pointer/arrow did not change how it looked.

• I used pointer to try to highlight a date in the PDF (a text report).
  • But all that happened was that the whole document briefly turned pale orange (odd, because I selected Green from the Highlighter color menu 1st time; then on 2d try, I selected pink.

So before I chalk this up as another Apple/Mac unexplained quirk, I would appreciate any input in terms of

1) how to get it to work right

2) out of curiosity, why does it happen so often in MacOS apps that the directions don't work (I am not a newbie, I have used Macs for more than 10 yrs).

Thanks in advance!