I guess you are taking about the Matlab Simulink based model, if this is the case, then, you must connect the "To Workspace Block" (2-no.) at the signals where you think the x-data and y-data belongs.
Assign the variable name of your choice, select the "structure with time" in the save format. Execute the simulation. After the simulation is completed, you will be able to get the variables in Matlab workspace. The data will be available in the table format once you double click on it. The tabulated data can be saved in the Excel format.