Navigation
The links across the top of your blog, where they should point, and how they behave on a phone.
Blog navigation is the set of links a reader sees on every page. It is separate from your product site's navigation, and it should usually point back into it.
What to put there
The links that let a reader who arrived from search find the product: home, pricing, docs, signup. A blog whose navigation only links to more blog is a blog that never converts.
External links
A link out to your product site can be set to open in a new tab, so a reader who clicks it does not lose the article they were reading.
On a phone
Navigation collapses into a menu below the theme's breakpoint. The live preview shows both widths it is built for, desktop and phone, so you can check the menu before anyone else sees it.
The footer
The footer carries your secondary links and the Blogged attribution. See SEO output for what else is emitted on every page.