One of the most basic functions of your site is to add a “Post”. Posts are different from “Pages” in that they can be categorized and are displayed chronologically. Posts are the equivalent of Articles or News Items.
This tutorial, while a bit dated now, still gives you a clear step by step on how to create a post with an image and some formatting such as headings. After viewing this video you will know how to add post by pasting the text from a document on your computer and how to add an image.