Go to your model, select menu Simulation>Configuration Parameters ..., on the left column, select Data import/export, tout is the default output of the time steps. You can check those options to specify inputs, output and signals. But you need to understand that the inputs/outputs are for root-level Inport and Outport block. Signal logging requires some other work. Best way for you to plot or see the graph is to drag a Scope block to your model and connect it to whatever signal you want to view.
Start with Matlab document, read the user guide on Simulink. There a few video to get you jump-started.
