requesting comments/questions for my NLAs explanation

When I started trying to figure out blender’s Non-linear Animation (NLA) system, I found a couple of videos that mention its existence, but I still had questions when I was done with them. I eventually achieved a working understanding through trial and error (mostly error). Faced with a question on stackexchange, I finally started to throw together a document that would help people get started:

Unfortunately, I’m pretty sure someone starting out with NLAs will have questions I haven’t answered. I also have not harvested links to some deeper information that might be out there.

If you veterans can remember some gotchas that you wish had been documented when you were starting out, let me know so I can add them.

If you’re about to start working with NLAs, review the document and tell me what questions it has not yet answered.

It could probably do with a few more annotated screenshots too.

Remember: the target audience is “someone who is starting out with NLAs”, and the goal is to quickly give them an understanding of how to use them; and recognize and repair the most common mistakes beginners make.