Adds light after what fact?
After the universe. See, God moves over the waters at the beginning, right? Before he creates light? How can there be water if there's no universe? There can't, so we know that the Biblical accounts says that first comes the universe, then water, then light.
But the cosmological model says that the universe comes first, light at the same time (since it's a fundamental force in the universe), and water after millions of years.
Clearly the accounts don't agree. The order is wrong. What's hard to understand about that?