Below Content Area
You can change the image used for this area within the customizer. Appearance > Customize > Layout > Footer
The footer content is made up of widgets. Appearance > Widgets > Footer. There are 2 footer widget areas. Footer and Copyright.
To set up the newsletter section you'll need to install and activate the MailChimp for WP plugin. See the plugin site for installation instructions. You'll need a free MailChimp account to connect it.
You can change the footer colors by going to the customizer. Appearance > Customize > Colors > Footer