button in the home page doesn't scroll down to the second widget

In the home page of Sydney demo the button under the header (“see more service”) scrolls down to the widget below. I’d like to do the same in my home page but I don’t know how.
I’ve written:
`#primary
in the header button, so it scrolls down to the first widget. But I don’t know what I should insert in the second button for scrolling it down again like in the demo.
There’s someone who can help me? Thank you.
Link to my site: http://www.robertaiuliano.it/