Help with child themes

Hi all. First I apologize for asking this again, but I didn’t get any useful help in the other forum. So I thought I would try again here.

I am trying to create a child theme for my WP site and one of my clients, but so far it hasn’t worked out. I have managed to get both child themes to appear on the Theme pages, but they don’t really help to keep my changes to the site, since they only have CSS stylesheets in them.

It seems the changes to the sites don’t stay, since I have updates in other files besides the CSS one. Also, images disappear when these sites are updated and I have to put all the images back every time I make any updates.

The whole reason I started trying to do this child theme stuff is because I’d heard that it makes things much easier when you do WP updates, and theme updates. I have been at this all day and it hasn’t made anything easier. In fact it’s been a real pain trying to find the info I need or get help with this from anyone.

If you can help in any way I would very much appreciate it.

Thank you.