The ISS is only visible when the sun is reflecting off of it. Those times are about 45 - 60 minutes before sunrise, or 45 -60 minutes after sunset. It will fade out of sight while still above the horizon as it passes into the earth’s shadow.
That is a good time to see other satellites, too. There were a couple of them visible last night in a polar orbit that we saw while waiting for the ISS to appear.
Not sure why it is so bright - that is above my pay grade. But the other visible satellites have to be much smaller than the ISS, but they can still be seen when the light is right.
Hope y’all have a chance to see it!