Joomla! Documentation™

• Login
• Click on “Submit an Article” in the user menu.
• Title your article in the text field labeled title.
• Add images to your document. You can select previously uploaded pictures, give a direct URL to an image or upload your own image. (optional)
• Add pagebreaks to your article. Pagebreaks make a table of contents for your article. (optional)
• Add a readmore tag to your article. Anything past the readmore tag can only be seen if the article is viewed individually. (optional)
• Type your article in the large text field.
• Return to the top of the page and click on the save button to create the article. Clicking on cancel will take you back to the homepage without saving.

Reference: http://help.joomla.org/ghop/feb2008/task056/