You will be able to set a title for the blog post, add the body content, also provide all the meta information such as extra details (Categories and Tags) and media (Featured Image). In that meta blog you can set the image for the thumbnail.
Same like page template, post type have "Page Option" as feature. But this option only available for standard post type and "album post type". You can set individual header and footer type, separate from the "Page Option" and "Footer Option". So your selected singular post will have different header and footer from other pages and posts.
Step by step :
1. Enter a title in the column that has been provided.
2. Fill the text editor with your content.
3. Add image here and the image will display as featured image.
4. Publish it!