It doesn't say anything about those things? Really?
Quoting from my post:
Upper section: latest post.
Middle section: “featured” posts (enclosed in a grey background).
Featured posts are any number of posts you decide to showcase by marking them as stickies.
The latest post and the featured posts can show up in full* or as an excerpt; option set in Appearance > Theme Options > General. The excerpt can be auto (beginning of post, text only), or custom, if you add content to the Excerpt field of the post editor.
If you set a featured image to your posts, the latest post will display that image above the post title [...]; the featured posts will include that image as a square thumbnail [...].
If you want images on the homepage but don’t like where and how the featured images are displayed, you can use regularly inserted ones instead, if you choose to display full posts, or include the image HTML in the Excerpt field, if you choose to display excerpts.
(Items in bold are links to the relevant Support docs.)