A potential energy surface (PES) scan is central to numerous problems in quantum chemistry, including identifying reaction mechanisms, reaction kinetics, transition states, activation barrier, etc. This work details the potential energy surface scan of the dihedral angle of the molecule n-butane using various open-source/freeware computational quantum chemistry software, including CP2K, GAMESS, NWChem, ORCA, Psi4, and PySCF. The input preparation, adopted methodology, execution flow, and results are discussed in detail, equipping readers with the necessary hands-on knowledge of computational tools to perform electronic structure calculations through a dihedral scan.