New pages in a Wiki are created after making links to them. The link in itself defines a new, empty page. Such links are called "Wiki words". Anything enclosed in a pair of square brackets is such a word.
If you've added Wiki words to an existing page, view the updated page content. You will see your Wiki words highlighted with a "?" link next to each one. Follow the link to fill in the contents for the new page.
Examples: [[C++]], [[Let's play again!]]