The tag
The self you're looking for isn't an object. It's a tag — a set of additions the mind makes to experience, fast and after the fact, so that experience arrives as mine, here, from in here, done by me. You can't look at an addition the way you look at a cup. You can catch it being added. It has four parts, and each one has a moment where it's catchable.
Location
The sense of being behind the eyes, looking out. Catch it by looking for the viewpoint — not the view, the point it's seen from. The visual field has no edge you can find and no back. There's no experience of "behind." Point at your own face: at the spot you're pointing at, what is actually there? Not a head. The whole scene, with no viewer in it. "Behind the eyes" turns out to be a few sensations — around the eyes, in the forehead — plus a belief about where you are. The sensations are findable. The viewpoint isn't.
Ownership
The "my" on everything: my hearing, my thought, my irritation. Catch it by timing. A sound arrives. Then, a fraction of a second later, I heard that. The ownership isn't in the sound; it arrives afterward, as a comment. The tag is always late. Watch for the arrival — the moment experience gets claimed. Then look at what the word "I" refers to: a word, pointing at a felt sense, and the felt sense is a sensation, in the chest or the head. A sensation can feel owned. It can't be an owner.
Boundary
Inside and outside. The sound is out there; the hearer is in here. Catch it by comparing. Take a sound and the warmth in your hands. Where is the hearing happening — not the source, the hearing? Where is the feeling happening? Two places, or one field with no wall between them? Now find the wall. The boundary is itself a felt thing: a sense of skin, a sense of in. One more sensation in the field. Not a line around it.
Agency
I'm doing the looking. Catch it by watching the start. Decide to look — and watch for the decision. It arrives the way a thought does, from nowhere you can find, and the looking is already under way before I looked gets stamped on it. Attention moved before you decided. Try to find the one who decided, before the decision.
Every how do I do this? is this part of the tag. It assumes a doer who needs a procedure. There is no procedure, because there is no one to run it. There is the question, posed in the presence of experience, and there is what's noticed. Anything beyond that is the tag asking for instructions. When how comes up, don't answer it. Who's asking? That's the loudest instance of the tag you'll get today.
What you'll find
The four parts come apart into sensations, images, words, and a view with no viewpoint. All of it is experience. None of it is the experiencer. The tag is the assumption that one of them is — and the assumption is only ever made after the fact, which is why it can be caught.