To introduce the topic to him I started reading Genesis on the Bible designed for children, which tells the story in an attractive and simple way that captivates the child's attention. We also read two beautiful poems from Creation by Gerald McDemott and Creation Song by Anna Scott-Browm and Elena Gomez.
Additionally I showed a really nice video available on youtube about creation -
Afterwards we created a wall called Creation where we pinned the number of the days God created the world. Each number is designed specifically to demonstrated what was created in the day.
My son also coloured pages about the story of creation. .
If you have any suggestion of materials to teach 1st graders about creation I would be thankful to receive it please :))). Hope you have a wonderful weekend. Thanks.