With the WooCommerce WordPress plugin you can easily create your own shop.
Once you install and activate the WooCommerce plugin you will have all the features that this plugin offers.
For a detailed explanation of how to use WooCommerce, we warmly suggest that you visit its official documentation as it is a valid point to learn from, regardless of the theme you are using: http://docs.woothemes.com/documentation/plugins/woocommerce