This is my favorite explanation.
Although I would also add “or observing your thoughts without judgment.”
There are so many ways to meditate, you can’t really do it wrong. I also have ADHD and I think it’s people like us who might benefit the most from carving out some quiet time for self-awareness. Of course your mind will wander. When you notice it wandering, that’s progress.
The way I do it is I just sit down on a cushion and focus on my body. Breathing is a great place to start because no matter where you are, you always have your breath. I might pay attention to what I see, for example a flickering candle, or I might close my eyes. If I have pain, I might even focus on that, to see if I can learn more about it. Then when I catch my mind wandering, which it will do, I label the thoughts very broadly (worry, political rage, planning, to name the most frequent patterns) and go back to focusing on the present. One thing I’ve started to do with intense emotions is not try to label them at all but just feel them in my body.
I truly never thought of meditation as an exercise in self-insight (however loosely you may define the self) until I read the book Why Buddhism is True by Robert Wright. It’s a look at Buddhist philosophy through the lens of evolutionary psychology and I learned a lot from it. It got me meditating again and has even informed my meditation practice. I’ll say, “Oh, that’s the brain’s status module trying to protect me” or whatever. Seriously, it’s a super cool book that doesn’t exactly walk you through how to meditate but explains the whole point of meditation rather well.
But you don’t have to read any books to do it. Just sit down and pay attention to what’s happening.