This is where if you have a pre-sell page you want as your home page you can select static and the dropdown menu appears for your pages. Select the page you want as your homepage and that'll be what people land on coming on from the search engines.

If you're just a want a blog style site you can select it to show your latest blog posts first. It defaults to that but unless you're want to build a following of people where you are getting tons of people want to know what your last blog post was and coming over then you may just want the static page option.