We pick up now in Genesis 1:2 "And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters."
What we has occurred to this point is the following.
Genesis 1:1 God created the heavens and the earth.
God created His court of angels and placed the hierarchy within God's government.
He made Lucifer the highest ranking Cherub and gave him the duty to provide the watch of the Garden of Eden.
We have learned that the Garden of Eden was a mountain that actually connected earth to the heavens - it was a common area.
Lucifer rebelled against God.
God had a trial, pronounced judgement, there was a war in heaven and Lucifer lost and was cast out of heaven off the mountain and to the earth floor.
While we don't absolutely know the timing of all this we do know that the heavens and earth were created and only had light no darkness. But in Genesis 1:2 we find that the earth was without form and void - Tohu wa-bohu. The verse goes on to tell us darkness was across the face of the deep. In that part of the verse we learn that the earth and heavens were separated and darkness filled the in-between state. Meaning there was no light on the earth.
We do not know for a fact what happened to earth as soon as Lucifer was cast out and God prevented light. But what we do know is that earth was a cold, dark wasteland. Some could speculate that it was this that caused the ice age and the flash freeze of the animals that roomed the earth at that time. Scientists cannot at this point determine the cause of the ice age but know it took place becasue we have the uncovered evidence.
What we additional know by reading the scripture is that Lucifer cast out of heaven had his name changed to satan and 1/3 of all angels followed him.
at this point in history God resided in heaven in love and light and satan resided on earth in fear and darkness. While the Universe was in this state the two (good vs evil) was separated but with God in control of governed over all.