To get things started, you need to have a store on Big Cartel. If you don't have one, get one here.
To add your store to your Virb site, first click the "New Page" button on the Pages tab. Choose Store from the list of available page types to bring up your page editor.
Click the "Connect to BigCartel" button, enter your Big Cartel store's unique url, and that's it! Your products and images will be automatically pulled into your page.
Problems? If you're experiencing issues with your store on Virb, we'd recommend just deleting and recreating the page to reset the connection with Big Cartel.