These instructions are totally missing the mark.
Many first time users will be trying to learn to contribute to an existing Joomla website where they see no "Usermenu" and no option to "Submit a page. Here it assumed that one starts with the Joomla Sample site. Therefore, first give the URL and put the reader on that page. Assume we are that empty page. The first step should be "Type your article in the large text field."; otherwise "Page break" and "Read More" make no sense.
Joomla is losing a potential user at step one. If this is characteristic of Joomla documentation, we have a bigger problem.
"Add images to your document. You can select previously uploaded pictures, give a direct URL to an image or upload your own image. (optional)" - No, you can not, at least not in the window we are. Please fix it.
"Add pagebreaks to your article. Pagebreaks make a table of contents for your article. (optional)" - This ain't possible either. please fix it.
"Add a readmore tag to your article. Anything past the readmore tag can only be seen if the article is viewed individually. (optional)" - This ain't possible either. please fix it.