A comprehensive guide to Best Practice Guidelines (BPG) in numerical simulations for Fuel Cells and Hydrogen applications has been one of the main outputs of the SUSANA project. These BPG focus on the practical needs of engineers in consultancies and industry undertaking Computational Fluid Dynamics (CFD) simulations or evaluating CFD simulation results in support of hazard/risk assessments of hydrogen facilities, and the needs of regulatory authorities. This contribution presents the BPG document and the BPG application through a series of CFD benchmarking examples.