When neutron stars merge, an explosive kilonova transient is produced and the heaviest (r-process) elements in the Universe are synthesised. By studying kilonovae we have an opportunity to understand r-process nucleosynthesis. To interpret kilonova observations, however, requires detailed modelling. In this article we discuss our simulation efforts towards interpreting kilonova observations and we highlight a number of uncertainties and challenges still to be addressed in kilonova modelling. We find that our simulation shows reasonable agreement with the observations of AT2017gfo, allowing us to identify that kilonova spectral features are likely blends of different features due to Doppler broadening. We also highlight the need to carry out 3D kilonova simulations. Further modelling is still required to understand kilonova observations.