Can somebody show me an example of the feature "Mold" use?

If by mold you mean "mold tools" then here is an example. The model I show is very simple. Molds can get much more complex, but the steps remain pretty much the same. So... start with simple. Even simple take many steps. I have attached the model file in roll-up, so you can step through to see how it works.
Hope this helps. PS SW also has a tutorial on their help page as well.

Answered with a tutorial: https://grabcad.com/tutorials/can-somebody-show-me-an-example-of-the-feature-mold-use

For some reason the left side of all screen captures got cut off. Try it, but if to "not clear" I can redo. But with model (attached)hopefully you will be able to follow along.
Reattaching model here...

http://grabcad.com/questions/tutorial-solidworks-mold-tools