A wiki is a website that anyone can edit, not just read. If you have never contributed to a wiki before and want to know how, this page is for you. Just follow the steps below. Once you've mastered what is on this page you should visit the Wiki Guide, which describes more about this particular wiki.
Step 1. Find the page you want to edit
In this example we are going to edit the Sandbox page (a page made just for you to practice editing on). You can get to the Sandbox page by clicking on a link to it (e.g., Sandbox) or typing "Sandbox" into the search box and clicking on the "Go" button. The page looks like this:
Step 2. Click on the "Edit" tab
Clicking on the "Edit" tab will take you to a special version of the Sandbox page that can be edited. It looks like this...
You may notice that it looks a bit different from the original page. For example, it shows "----" instead of a horizontal line that goes all the way across the page. Likewise, it shows the text: "== Header 1 ==", instead of a properly formatted section header like you see on the regular Sandbox page. For most contributions you make you won't need to use the special "wikitext markup" characters, just let them be. (If you do want to see them in action just visit Help:Editing).
Step 3. Make your edit
All of the text in the box can be edited. In our example, we will add the text: "Hello World" just before the horizontal line. To do this, we use our mouse and click on the part of the text that is right before the "----" line. Then we type in "Hello World" just like we would if we were using a word processor. Notice that there is a blank line above the words "Hello World". This blank line means that "Hello World" will show up as a new paragraph on the page (with a space before it).
Feel free to make other edits and even try out some of the special formatting if you're feeling brave.
Step 4. Save your edit
Once you have made your changes to the Sandbox page, you will need to enter a summary of your edit and save your changes. In the following example, we have entered a brief explanation of our edit in the "Summary:" box (i.e., "Added hello world"). Then all we do is click on the "Save page" button at the bottom.
The Help:Editing page explains the other buttons such as the "Show preview" button.
Step 5. View the edited page
After saving the page you will see the updated Sandbox page, which should look like this:
In this example we have edited a page without logging into the wiki. Although you can do the same, we generally recommend that you create an account and login before making edits. That way others will know who made the edit and can decide if it needs reviewing. The Help:Logging in page describes why you may want to create an account and how to do it.