Here is a basic but very effective little exercise.
Please sit comfortably, and ask yourself:
What am I noticing right now?
Allow yourself effortlessly to notice what presents itself to you, with no attempt to concentrate or focus on anything particular.
There are sights; sounds; smells and tastes; feelings of touch; the feeling of your posture and movements of your body; internal sensations in your body; emotional feelings or mood states; and a whole variety of thoughts: inner dialogue or monologue; images; memories; fantasies of the future; images of yourself; and the central thought, 'I'.
All these various experiences arise, interact, and pass away, in the field of your awareness.
They are all (obviously) happening NOW.
It is as if you are just resting, watching the play of experience.
Now: WHO is watching this play?
This is NOT a conceptual or philosophical question; it asks that you observe, pay direct attention, to the one who is experiencing all that arises; the 'I', the awareness.
As you explore this, you will find that you can't actually find the 'I'. Anything you find (such as sensations of your body, feelings, or thoughts in your mind) is clearly not 'I', the experiencer, but just part of the flow of experience.
Rest in this place, where you cannot find the experiencer. There is just a spontaneous flow of sight, sound, sensation, feeling, thought; but there is no-one watching.