The Habitable Worlds Observatory is set to provide groundbreaking imaging and spectroscopic observations of galaxies, which will greatly enhance our understanding of how galaxies form and evolve. To fully capitalize on these new observations, it is crucial to develop advanced numerical models that can accurately predict the complex physics involved in galaxy formation. In this presentation, I will introduce an interstellar medium (ISM) model that self-consistently incorporates the effect of radiation fields, dust physics, and molecular chemistry (H2) in galaxies. I will showcase the model’s success in predicting both the integrated (such as stellar masses and star formation rates) and resolved (such as dust content, emission lines, etc.) properties of high and low redshift galaxies. Lastly, I will discuss the limitations of current models and outline improvements to both the physical models and numerical algorithms that will allow us to effectively interpret data from next-generation telescopes.