Creating a "blog" and creating a "post" are two separate actions. Posts belong to blogs, or put another way: A blog is a collection of posts.
1. Hover over the '+' and select Create Blog Post. (Note: you need appropriate permission to create and edit blog posts. If you need access, please contact a site admin.)
From here, it is very similar to creating an article. To edit, you will check-in and check-out posts. To publish, you can select 'Now' or 'Later' and schedule for a later time
2. Create a slug, headline and begin building the article in the content/abstract area. The same formatting options are available for blog posts as articles.
3. Be sure to select the correct blog that you want the post to show up in. Under Blogs there is a dropdown list of all available, published blogs.
REMINDER: Blogs display in chronological order, from most recent to least recent. Blog posts don't carry a weight, which means that article content and blog content cannot be displayed together in the same list. Merging these two content types in a single display element is a common support request, but alas, it won't work. A workaround is to have a content block of articles right next to a content block of related blog posts.