To edit any page, click the Pencil icon in the upper right edge of each page.
To create a new page, browse to the section of this wiki where your page-topic will fit best. You can then edit that section page to create a link to your new page, like this…
[[name of your page]]
Once you save your edit, the “name of your page” becomes a clickable link. Go ahead and click it.
The wiki will say that page doesn't exist but that you can create it. So click the pencil icon on the right to create your page and start adding content.
You can use this Dokuwiki Syntax Guide for formatting instructions.
If you need any more help, drop by the wiki knowledge base thread in the forums and ask away.