I have found, working with many people over the years, that in some cases definitions help, in some cases they hinder, in some cases they don’t make much difference.

The key, at least in my experience and in research I’ve seen as a psychologist, is practice.

And it does seem that some sort of mindful awareness is key.

The following is not a universal recommendation, but I would say for most people starting not with words or definitions, but sensations, is key.

This is also especially helpful for improving sleep:

Start with the head (oops, there’s a word:>)). Just notice the different sensations in different parts fo the head. If you must use words, you might notice more or less intense, pleasant, unpleasant, etc.

Then go through the body in a very relaxed way - torso, arms, pelvis, upper and lower legs, feet.

Do this for maybe 5 minutes and gently drift off to sleep (if getting to sleep takes 15-30 minutes, that’s fine. If more, you might get checked out for insomnia)

After a month or so, see if you can notice verbal thoughts. Notic without getting lost in them.

To much to go further in a brief comment bt any basic book on mindfulness (or just a good article online) can get you through noticing sensations, thoughts, feelings and emotions.