Editing most NC-wiki pages is not very difficult. Simply click on the "edit this page" tab at the top of a Wikipedia page (or on a section-edit link). This will bring you to a new page with a text box containing the editable text of the original page. You should write a short edit summary in the small field below the edit-box. When you have finished, press the Show preview button to see how your changes will look. You can also see the difference between the page with your edits and the previous version of the page by pressing the "Show changes" button. If you're satisfied with what you see, be bold and press the Save page button. Your changes will immediately be visible to other NC-wiki users.
You can also click on the "Discussion" tab to see the corresponding talk page, which contains comments about the page from other Wikipedia users. Click on the "+" tab to add a new section, or edit the page in the same way as an article page.
You should remember to sign your messages on talk pages and some special-purpose project pages, but you should not sign edits you make to regular articles. In page histories, the MediaWiki software keeps track of which user makes each change.
When editing an article page on this site, a logged-in user can mark that edit as being "minor". Minor edits generally mean spelling corrections, formatting, and minor rearrangement of text. It is possible to "hide" minor edits when viewing the recent changes. Marking a significant change as a minor edit is considered bad behavior, especially when it involves the deletion of some text (not counting errors such as repeated words). If you accidentally mark an edit as minor, you should edit the source once more, mark it major (or, rather, ensure that the check-box for "This is a minor edit" is not checked), and note that your previous edit was major in the new edit summary.