5. About Page
This page uses "Default Template" you can find inside the "Page Attributes".
5.1 Left Content Part
First comes the featured image you can include but you don't have to. Under the feature image is the page title. Under the page title is the content from the editor.
5.2 Sidebar
To fill it with content navigate to Appearance > Widgets > Sidebar and add your content inside it. Special Jetpack feature "Jetpack Widget Visibility" allows you to have different sidebar content on different pages using the same sidebar. That means you are able to have one content inside the sidebar on the about page and other content inside the sidebar on the, for example, "News Page". This gives you a great amount of creative freedom! Read more about it here:http://jetpack.me/support/widget-visibility/