HeH is a molecular system with only two nuclei and three electrons, which allows for accurate structure calculations. Here we study electronic resonant states of HeH. We combine quantum chemistry calculations with electron scattering calculations to compute molecular potential energy curves, non-adiabatic interactions and autoionization widths. The goal is to obtain a very accurate and consistent set of molecular data and then use it to study a number of reactions. The processes we intend to study include mutual neutralization, dissociative recombination, ion-pair formation, penning ionization, vibrational- and dissociative excitation. In the talk, I will present our approach to compute the molecular data and then briefly describe how we study the nuclear dynamics for modelling the different processes.