The Primary Sidebar is a very versatile widget area that you can use to place ads, tell your readers about yourself, highlight some of your older content, add a search bar, or share information of any kind. On our demo site we've added some ads as well as a newsletter opt-in and some featured posts to our sidebar.
To configure the Genesis eNews Extended plugin for the Primary Sidebar you can drag and drop a Genesis eNews Extended widget from the Available Widgets area to the Primary Sidebar widget area. This article will get you going in the right direction on how to get your newsletter service setup with Genesis eNews Extended.
You can see the screenshot below for how we've setup the Cravings Pro Featured Posts widget in the Primary Sidebar: