The complex systems that arise in biology, including biochemical reaction networks, signaling pathways, cell-cell interactomes and gene regulatory networks, are challenging to decipher. One valuable approach is offered by “dynamical systems” or “systems biology”, which has a rich history in mathematical biology and whose use is being propelled by recent advances in computational science. I will give an introduction to this method, including simple examples of ordinary differential equations, (i.e. how to go from a cartoon arrow diagram to a quantitative mathematical model) and provide shared code (Matlab/Python/Julia). This talk will be accessible to audiences with no background in mathematics or programming