The paper investigates hadron-hadron collisions at high energies using the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model. This microscopic transport model describes hadronic interactions at low and intermediate energies ($\sqrt{s} < 5$ GeV) through interactions between known hadrons and their resonances, while at higher energies ($\sqrt{s} > 5$ GeV), the excitation and fragmentation of color strings dominate multiple particle production. The model shows good agreement with experimental data over a wide range of hadron-hadron center-of-mass energies. The paper discusses the motivation for studying these collisions, the UrQMD approach, and the detailed elementary hadron-hadron interactions used in the model. It also covers the treatment of resonance and string formation, finite size effects, transverse momentum generation, and predictions for observables. The Additive Quark Model (AQM) is used to calculate unknown cross-sections, and the effects of color opacity and transparency are explored. The paper concludes with a summary and conclusions.The paper investigates hadron-hadron collisions at high energies using the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model. This microscopic transport model describes hadronic interactions at low and intermediate energies ($\sqrt{s} < 5$ GeV) through interactions between known hadrons and their resonances, while at higher energies ($\sqrt{s} > 5$ GeV), the excitation and fragmentation of color strings dominate multiple particle production. The model shows good agreement with experimental data over a wide range of hadron-hadron center-of-mass energies. The paper discusses the motivation for studying these collisions, the UrQMD approach, and the detailed elementary hadron-hadron interactions used in the model. It also covers the treatment of resonance and string formation, finite size effects, transverse momentum generation, and predictions for observables. The Additive Quark Model (AQM) is used to calculate unknown cross-sections, and the effects of color opacity and transparency are explored. The paper concludes with a summary and conclusions.