Motivated by the experimental discovery of superconductivity in the trilayer Ruddlesden-Popper nickelate superconductor La4Ni3O10, we investigate the electronic structure for both the ambient pressure and high pressure phase. A two-orbital three-layer minimum model is constructed from maximally-localized Wannier orbitals of Ni e_g character. Furthermore, systematic dynamical mean-field theory (DMFT) and quantum Monte Carlo (QMC) simulations are performed, where we confirm the picture of orbital-selective correlations and discuss the role of Hund’s coupling J, and it’s competition with the interlayer coupling t_{\perp} and Hubbard U, in the description of the low-energy correlated electronic structure and pairing tendencies.