Molecular Dynamic (MD) simulations are fundamental to understand the mechanism of biological systems. This workshop aims to provide an introduction on the use and on the features of a well-established and highly used package in the field GROMACS. The workshop covers an introduction to MD simulation, to accelerated weight histogram methods and to GraphicsGraphical Processing Units (GPU) performance. At the end the participants will be familiar with the features of GROMACS code, and they will be able to set up and perform molecular simulation on the covered topic.