You can use the subscribe section to get subscribers to your email list. You can also leave this section out if desired. In order to make use of it, you will first need a service for your list. Mailchimp is easy to use and is free for a basic new list.
Make sure that you have the Genesis eNews Extended plugin installed and activated.
Set Up of the Widget
Navigate to Appearance-Widget. Click Genesis eNews Extended and add it to the Homepage Subscribe Bar area or drag and drop it in that area. You will now need to set up the widget for your service. This page has tutorials for all of the common services.
If desired, you can also install a subscribe widget into the blog sidebar of the theme using the same widget.