User:Proteins/Start editing tutorial
In an earlier tutorial, we described how to start aItalic textItalic text' new article. But what if your article exists already and you'd like to improve it? Here are three methods to begin editing an article. In later tutorials, we'll show you much more about editing; hang on!
A video has been made of this tutorial.
Edit this page
The simplest approach is to click on the "edit this page" tab at the top of the article, which is sandwiched between the "discussion" tab and the "history" tab. This opens the editing window for the whole article.
The layout of the edit window is as follows. The top tells you which article you're editing and its total size. Second comes a brightly colored toolbar of 22 buttons that will help you with editing, as you'll see in the next tutorial. Third comes the editing textbox where you should add text. Below that, you'll find an edit summary textbox into which you should write a summary of your changes before clicking on Save page. Below that, are the two main buttons you'll use: Save page and Show preview. The latter button shows you what the page will look like, but doesn't save it. Finally, if you click on the Editing help link to the right, a new window will open with a "cheatsheet" of commonly used editing commands.
Edit a section
A drawback of "edit this page" is that it opens the whole article. For short articles, that's not a problem, but as articles become longer, it becomes harder and harder to find.
The most common method is to choose a section to work on and click on the edit link at the far right.
Talk pages only: The "+/new section" tab
On talk pages, you may see a tab next to the edit tab labeled "+" or "new section". Clicking on that tab opens an edit window that will append a new section to the talk page. It's helpful for people who are watching a talk page to know that a new topic of conversation has been started, in case they would like to join in.
Three things to notice about editing
You should notice three things in the video. First, you don't need to hit return when you reach the edge of the editing window. Just keep typing and Wikipedia will format everything nicely once you click on the Save page button. Secondly, paragraphs are separated by exactly one blank line. More than that, and unsightly white space begins to build up in the article. Third, sections are created by enclosing the section heading with at least two equal signs on either side. A subsection is created with three equal signs, like so...
...and a subsubsection with four equal signs, like so...
and a subsubsubsection with five equal signs, like so...
Note that all these levels of subsections get their own  link, and are listed above in the Table of Contents. Most articles longer than three sections will have a table of contents at the beginning for easy navigation.