How to update Active Theme with WPA-commerce?

I'm a total novice to website building and not very confident with computer technology so I apologies if this sounds like a stupid question but, I have just installed WP and a responsive theme from "storefront" as I understand this theme works well with WP e-commerce which I've also installed. however, the message below appeared on my dashboard : -

WP e-Commerce is ready. If you plan on editing the look of your site, you should update your active theme to include the additional WP e-Commerce files. Click here to ignore and remove this box.
but there's no information on how to do this. any suggestions would be greatly appreciated.

I suggest you try the vendor of wp e-commerce http://getshopped.org for support? (it is really plugin-specific)