Siddhartha was born in India as a prince in the 6th century b.c.e. His mom died when he was born and so his dad wanted to keep him protected and isolated from the world. When he was little a holy man said he would become of great thing and one of them was a spiritual leader.
One day Siddhartha left his palace with his tutor and saw an aging man, a sick man, and a dead mans body. When he saw those three men, Siddhatha asked if he would end up like them and his tutor said yes. Siddhatha never left the palace so he of course didn't know anything.
Siddahartha wanted to become a sick man so he left his palace, wife, and kid. He wanted to personally find himself so that's why he left.
Siddhartha wanted to find himself and become a new person badly but he ened up almost starving himself to death.
After starving himself, Siddhartha found a sense in Buddhism and wanted to become a buddha. He then followed the rules and steps to become a buddha.
When Siddhartha finally became a Buddha, he gained many followers and encouraged others to become buddhist. Throughout the journey he lost many followers but that was okay for him because he didn't want any. Siddhartha taught Dharma and ended up being one of the most successful buddha ever.