It took me months to get the right combination of my old digital camera and my various computer protections and things like that before I could get pictures to post. The help section here does have a lot of good info!
https://www.quiltingboard.com/qb-help-center-f27/
For me it turned out that my file sizes were too big, although my software has been updated I have limited options with my old camera and I go to this site to reduce the file sizes, I just use their defaults and download my pictures through the site so two clicks and I'm done. No affiliation to the site, but it is easy and doesn't set of my virus protections.
https://www.reduceimages.com/
The other thing still trips me up about half the time -- once you have attached your pictures, you have to adjust the window and stretch it to the far right so you can see the upload button!
I've never been able to use the paper clip icon and I don't do well inserting the pictures in the text, just the thumbnails at the bottom. so I use the Go Advanced options.
PS/Edit -- and then the other thing to be aware of is we have limited time to edit our posts. That's a common forum thing so that people don't do bad things and then attempt to cover up. It's not very long -- maybe 5 minutes? After that you have to do a new post.