How did the earth form?
It formed from dust!
The Earth right now is believed to have been formed by dust billions of years ago. After the formation of our sun around 4 billion years ago, there was a huge dust cloud that surrounded the sun. These dust particles moved and even collided with each other. Sometimes these dust particles would stick to each other and other times they would bounce off. Eventually, the dust clumps become big enough to become rocks, then boulders and then they eventually collided and coalesce enough to form a planet like Earth!
This process took an extremely long time and only accounts for the solid Earth! This explanation doesn't necessarily explain how we got oceans on Earth or how we got our atmosphere.