Since you have mapped the functionallity of the MyAdderModule to a single primitive now, you might as well replace it in the examples system. Switch to the model editor window containing the MyAdderSystem (or open it again if you've already closed it).
If you've followed the suggestions regarding the naming of ports and parameters throughout this excercise, it is very easy to replace the model instance. Just drag MyAdderPrimitive from the tree view over to the instance of MyAdderModule (you'll notice a change of color when you're right) and drop it there. Since both module and primitive have an equal number of ports which are equaly named the relations between the instances are preserved. Also the parameter ScaleFactor is still linked to the system parameter. You may save the system now and run it again. You will observe the same results as with the module.