Imagine the spiral galaxy in the center is the Milky Way, where you live.
Move the slider to change the scale factor.
Observe that the more distant a galaxy is initially, the further it moved and therefore the faster it speeds away from you. This is Hubble's Law.
————————————————————————————— Step 2:If one is living in another galaxy, he/she will see the same thing as you do.
To illustrate that, place one of the galaxies back to its “original” position.
You can now see that Hubble's Law is true also for observers in this galaxy. This illustrates how we are not at the center of cosmic expansion; in fact, there is no center.