Creating an article in Dokuwiki is very simple. Any link that is red is to an article that doesn't exist. You can find these pages either by searching for the page or by finding them in already existing pages. You can also quickly create a page by typing in a non-existent page name in the URL.

For example, here is what a page that doesn't exist yet looks like in search results:

Here's what a page that doesn't exist looks like when linked to in an existing page:

When the page doesn't exist, you'll be informed as such. If you have permissions to create the page, just click on the create page link.