Ask HN: How do you adquire basic cumputer literacy?

So here is the backstory. My mother's supervisor sends her an e-mail with "texts" as a jpg image. My mother's works with computers mostly involve pdfs and office documents.

When she tried to open the jpgs, which she thought where pdfs. She contacted me because "it wasn't working".

Would she had carefully read the screen, the info was there. Then she would have need to install an image viewer. That is what I would have done. But, how do you learn that that is the solution?