Each purchase is associated with a particular user. You are required to login before purchasing, when the transaction occurs the order is recorded for that user and the items available to them from the download center while they are logged in. It is this login info that you need to gain access to the products. For eCart the product is an extension that is installed into Dreamweaver. When installed it wil allow you to add functionality to your pages for commerce. You can then upload these files to your live server to make use of them in your site.