In the Body field goes the full text of the article. Depending on the text format selected, various buttons are available from the editor for formatting the text. My text looks as follows:
Today Sasha Gabor discovered donuts! They're not exactly healthy diet fare for a dog, but she didn't seem to mind.
Enter some text for your article, and format some of it using the B (bold) or I (italic) buttons. When you have entered it, click the Source button to see what the actual HTML markup looks like. Mine shall look like this:
<p>Today Sasha Gabor discovered <strong>donuts</strong>! They're not <em>exactly</em> healthy diet fare for a dog, but she didn't seem to mind.</p>
If you ever need to customize the underlying HTML of the body text, this is where you can do it. Click the Source button again to return to WYSIWYG mode.