You can simulate a model at any time simply by clicking the Run button on the Model Editor displaying the model. See Start a Simulation.
However, before starting the simulation, you might want to specify various simulation options, such as the simulation's start and stop time and the type of solver used to solve the model at each simulation time step.
With Simulink® software, you can create multiple model configurations, called configuration sets, modify existing configuration sets, and switch configuration sets with a click of a mouse button (see Configuration Reuse for information on creating and selecting configuration sets).
Once you have defined or selected a model configuration set that meets your needs, you can start the simulation. The simulation runs from the specified start time to the specified stop time. While the simulation is running, you can interact with the simulation in various ways, stop or pause the simulation (see Pause or Stop a Simulation), and launch simulations of other models.
If an error occurs during a simulation, Simulink halts the simulation and the Diagnostic Viewer pops up to help you to determine the cause of the error.