Life is essentially an organised network of chemical reactions (metabolic pathways) that can create copies of itself given a source of energy. How was this complex reaction network formed from the simple molecules that were present on the early Earth? I will answer this question by simulating how simple reaction networks evolve starting from different combinations of building blocks and reaction conditions. Computer simulations will allow me to search many more combinations than is possible experimentally, thereby increasing the chances of finding reaction networks that resemble those found in modern cells. Finding a plausible explanation for how life originated on Earth will not only have profound implications for how we view ourselves and other species, but also give us a much better idea of how likely life is to have evolved on other planets.