Once you've finished adding all of your content to the article, you can save your edits by clicking on the "Save" icon, found on the right hand side of the Dashboard (see below). Saving will allow you to preview your content, but note that the article will not be visible in your live app until you publish it.
In order to publish your article and make it live for all your users to read, you will need to click the "Publish" icon! It can found on the right hand side of your Dashboard (see below). Once published, all your users can read your article!