This section allows you to manage, customize, create your site wide Footer. You can do so through three options, the first two are the ability to choose the specific color scheme and including SnapPages branding on your Footer.
The third option you have is the Add a Block. Much like you pages your Footer is built our by using the available blocks. All you have to do is simply drag and drop in the blocks you want!
To learn more about building out pages and what you can do with Blocks check out our Page Editor section on the Help Center for all sorts of articles!