The book of Moses talks about Moses' communication with God and in this the creation of the earth was revealed to him by God directly. Moses then wrote this down and this is the origin of the book of Genesis. Since the bible has some parts left out the creation account of the book of Moses goes more in depth than Genesis and shows how the creation of the earth was involved in the grand scheme of things.
The parts of the book of Moses that talk about the creation and the Garden of Eden are Moses chapters 2-4. As a sample, I will be posting Moses 2:1-12.
1 And it came to pass that the Lord spake unto Moses, saying: Behold, I reveal unto you concerning this heaven, and this earth; write the words which I speak. I am the Beginning and the End, the Almighty God; by mine Only Begotten I created these things; yea, in the beginning I created the heaven, and the earth upon which thou standest.
2 And the earth was without form, and void; and I caused darkness to come up upon the face of the deep; and my Spirit moved upon the face of the water; for I am God.
3 And I, God, said: Let there be light; and there was light.
4 And I, God, saw the light; and that light was good. And I, God, divided the light from the darkness.
5 And I, God, called the light Day; and the darkness, I called Night; and this I did by the word of my power, and it was done as I spake; and the evening and the morning were the first day.
6 And again, I, God, said: Let there be a firmament in the midst of the water, and it was so, even as I spake; and I said: Let it divide the waters from the waters; and it was done;
7 And I, God, made the firmament and divided the waters, yea, the great waters under the firmament from the waters which were above the firmament, and it was so even as I spake.
8 And I, God, called the firmament Heaven; and the evening and the morning were the second day.
9 And I, God, said: Let the waters under the heaven be gathered together unto one place, and it was so; and I, God, said: Let there be dry land; and it was so.
10 And I, God, called the dry land Earth; and the gathering together of the waters, called I the Sea; and I, God, saw that all things which I had made were good.
11 And I, God, said: Let the earth bring forth grass, the herb yielding seed, the fruit tree yielding fruit, after his kind, and the tree yielding fruit, whose seed should be in itself upon the earth, and it was so even as I spake.
12 And the earth brought forth grass, every herb yielding seed after his kind, and the tree yielding fruit, whose seed should be in itself, after his kind; and I, God, saw that all things which I had made were good;