The precambrian age is the first age in earth history. This is when the earth was created. Ocean start to cover the earth and oxygen comes in the atmosphere. The earliest life started. But the late in the precambrian age there was a mass extinction killing most animals.
The earth was formed around 4,600,000,000 years ago. The earth was formed by material that came from the sun when it ignited. The sun pushed material outwards and the material collected together. The collected material had mass and gravity, this is how the earth was formed. The moon was formed when a piece of the earth split away from the earth the earth had enough gravity to keep it in orbit.