James txs and even with your instruction it was not clear how to get out of the highlight tool to select text.
Just in case you were endlessly clicking on the highlight tool without success (yep, me)...it's because the color of hovering is almost the same as when the highlight tool is switched On. Hover over the highlight tool and it's a light gray, click -- if the highlight tool is on it's a paler gray, if the highlight tool is off there is no gray (tricky to see if you have your screen brightness down.)
You'll know when the Highlight tool is selected if it is a super pale gray. Yep. I didn't notice the change at first because it's a similar gray when you hover over the tool. To test: click the Highlight tool and move the cursor away from it a few times to see the difference between On/Off.
Also, ditto for the selection tool -- if selected it turns blue.
To be honest. I still am not getting this right still. Am I'm not really tech-phobic. So a bit confused.