At the top of each section of an article (if it has sections, that is), located on the far right of the screen, is an [edit] button. The button is offset slightly above the section, and sometimes new users get confused and think it belongs to the section above it. When you click on the edit button, the edit window opens up, displaying the source text from the section immediately below the edit button. Please use these whenever you can. You can set your preferences to have the section headers themselves to act like the [edit] links.