The one paragraph version of "how do I edit Wiki pages" is in the Wiki Quick Start.
For a little more detail, consult MediaWiki's guide here: http://meta.wikimedia.org/wiki/Help:Editing or, alternatively (for the entire index of Editing materials, and for _really_ detailed info on everything: http://meta.wikimedia.org/wiki/Help:Contents#For_editors
We will eventually either copy these pages to our site or paraphrase them and copy them. Sorry for the slight inconvenience.
The MythTV wiki has chosen to make use of the MediaWiki categorization features to better organize content.
A top level category named "Knowledge Base" has been selected. All other categories should be placed into this category which makes them automatically sub-categories.
How do I categorize a page?
Simply add the line
where Name is the name of the category, to any article to put it in a category. Editing a category page will likewise categorize the category making it a sub-category rather than a linked article.
What category should I use?
Use what makes sense. Look at the list of categories from the Special Pages link to the left to see what already exists. If nothing matches, create one, but be sure to edit the new category page and place it into a category, even if it is "Knowledge Base"
Can I categorize a page more than once?
Yes, just add more Category lines to the page and it will exist in multiple categories.
How do I categorize a category?
Categories are pages, just as all other pages are; in addition to the list of pages (and subcategories) in a category, there's a space at the top for content which describes the category. In addition to this "real" content, you can also include Category tags, which will make that category into a sub-category of the Category whose take you use.
This is really less complicated than we make it sound here; look at the source for a few category pages, and it will likely become clear to you.