With my group and international collaborators I am investigating, using numerical simulations, how star clusters, galaxies and the Universe evolve and form. For this we are using a host of computer codes ranging from Nbody methods which allow precise and accurate integration of compact few-body stellar systems to codes specially developed in my group to evolve galaxies in Milgromian gravitation (i.e. without dark matter). The aims are to (i) understand how ejections of massive stars from their birth clusters affect the evolution of galaxies, (ii) how the observed very significant regularities of galaxies arise (these being unexpected if using the dark matter approach), (iii) where the matter feeding galaxies comes from and (iv) a new cosmological model which is not based on dark matter.