Begin with a simple numerical problem or Xcos model whose expected behavior is known. Check units, initial conditions, and solver choices before adding detail. Save scripts and model files together, and compare simulated outputs with analytical results or measurements when available to avoid mistaking a plausible plot for a validated model.
This is best suited to engineering calculations and dynamic-system teaching. Before committing a larger project, account for these trade-offs: syntax differs from other numerical tools; complex simulations require careful solver setup.