How must the first life have originated on the Earth according to Darwin?

According to Darwin’s theory of evolution, life on Earth originated in the form of a hot sphere which gradually cooled down and then afterward environment was formed. Simple elements were present previously which combined via chemical reactions to form simple compounds which on further reaction resulted in complex compounds resulting in the formation of essential components of life such as carbohydrates, proteins etc. Suddenly a living organism originated which gave rise to present life forms by organic evolution.