To start editing a page, click the Edit this page (or just edit) link at one of its edges. This brings you to the edit page: a page with a text box containing the wikitext: the editable source code from which the server produces the webpage. If you just want to experiment, please do so in the sandbox, not here.
Type your changes
You can just type your text. However, also using basic wiki markup (described in the next section) to make links and do simple formatting adds to the value of your contribution.
Summarize your changes
Write a short edit summary in the small field below the edit-box. You may use shorthand to describe your changes.
When you have finished, click Show preview to see how your changes will look -- before you make them permanent. Repeat the edit/preview process until you are satisfied, then click Save page and your changes will be immediately applied to the article.
Providing references to facts in your articles is an important part of being a thorough editor. On LGPedia you can use Cite.php to easily and consistently document your references in an organized way. See Help:Footnotes for more information.
I need more help!
For other questions, feel free to leave a question on the talk page of one of the admins of the LGPedia: