How do I start learning about software development?

I don't need to learn how to code. I just need to have a solid foundation of the concepts or maybe be able to read some code.

What resources should I check out? Which programming language do you suggest I start trying to learn or understand?

I don't have a technical background. I do know HTML, CSS, and a bit of JavaScript, but that's about it, and I'm not sure if that'll be important.

Any tips are appreciated. Thanks!