To access the blog settings open: Themes > Customize theme In the preview window open your stores blog page.
Within your stores blog we have added the options to include a banner image which will display full width and also some additional content that would allow you to place more content to describe your blog or provide an introduction.
Image - Add am image that will display at full screen width, we recommend 1920px wide x 500 - 600px tall
Text - Add some text to provide the blog introduction as mentioned above
Show published date - Toggles the visibility of the published at date on the blog overview page for your articles