When you work with something constantly things start to become natural and it can be hard to understand why people can't fathom the simplest of things. When you realise that most people wont learn something they don't need too. It becomes a lot more obvious why they struggle.
For example I know quite a bit about computers but know nothing about going to the gym nor do I want to learn about it. So asking me how a treadmill works is probably as baffling to me as it would be me asking the average non-technical person how to zip a file and email it.
A while back people were pushing to teach every child to code. Some people will simply not understand or want to do this, instead they should teach them the basics to get by and to at least understand when they are having the wool pulled over their eyes. I don't need to know how to fix a plumbing issue, I just need to know that something is clogged in the pipe in a certain area to help the plumber out. This list will give you a head start to becoming a bit more self sufficient when it comes to using tech. Then the rest should become a bit more natural and you'll pick it up over time.
"Knowing computers" today is more than just knowing Office, or knowing how to attach a file. Today's connected world is way more complex than any of us realize. If you're a techie, you're very likely forgetting how far you've come!