You're always able to create a page on a wiki, no matter what your admin status is.

You can simply do it by clicking on the "Contribute" button on the right top of the wiki. Click in the dropdown menu on "Add a Page", insert a title and you can start editing on that page.

Another way to create a page is by clicking on a red link.

Another way of creating a page is by typing the page name in after the webaddress. For example I want to create a page with the name "Create a Page" on this wiki, you can do it like this:
When you're on the page click on the "Edit" button to start.

Don't forget to publish the page after editing, which you can simply do by click on the "Publish" button in the right rail.