So space is “dragging” our own galaxy through... through what... space?

Does that mean that when I’m running away from a lamp post, I’m “moving”, but if someone puts me in a car, then the car “drags” me away from the post, but I’m not really “moving” relative to the post? The car is just “dragging” me along with it, but I’m “stationary”? What branch of physics is this?

Explain to us exactly how space “expands”. Do space particles get bigger, or what? Does “new space” fill in the gaps in the “old space”? Does the old space “stretch” or what?

You keep saying that “space expands”, but I want to know how space expands. What is the physical function of “space” that allows it to “expand”?

If we’ve got two rocks in front of us, and we move them apart, we see that the space between the rocks has “expanded”, but that’s because we moved the rocks. So how can the galaxies be moving away from us, thereby causing their light to redshift, yet you say they are “not moving”? Please explain in detail how that physically works.