Light-headedness is a signal, not a milestone.

The advice in most classes is correct and useless in equal measure: relax the shoulders, breathe into the belly, find your edge. None of it tells you what to actually do with your body in the next thirty seconds.
So here is the practical version. Set a timer, because without one you will either stop early or drift well past the point where this stops helping. Move into the position slowly enough that you could stop at any moment along the way. Then do very little for a while, which is the part almost everyone skips.
The sensation you are looking for is clear but unremarkable — something you could hold a conversation through. If it sharpens, if it migrates into a joint, or if you notice you are holding your breath, you have gone past the useful part. Come back until it is dull again, and stay there.
Frequency does the work here, not intensity. Three short sessions across a week change more than one long one, because the nervous system updates on repetition rather than effort. This is unglamorous, and it is also most of the trick.
Expect the first fortnight to feel like nothing is happening. That is normal and it is not a reason to add more. The change shows up in ordinary moments — standing up from a low chair, reaching behind you in the car, falling asleep without rehearsing tomorrow.
None of this needs equipment, a class, or a free hour. It needs the same ten minutes, often enough that your body stops treating the position as unfamiliar.