[Theme: Expositio] making a button appear to scroll

Hi Everyone. I have built small site for my client but they have now decided that it feels difficult to understand you have to scroll right when you first land on the home page. So Im on the lookout for a button which doesnt have to be pressed, just pops up for a few seconds to show the site needs scrolling across to the right. Does anyone know of a simple overlay (keeping everything active so not a light box).

Here is the site:
http://www.mooredesign.info

Thanks