there are two ways to create a new page.
a) edit a page. In the text place the pagename betwen double brackets
save the page... when viewing the page you will see a linked ? besides the new pagename. Click and the you will got to the new page editor... the first time you edit a page you can switch to the markup format you wish to use (dfwiki for mediawiki markup format, ewiki for old wiki syntax I would not do it, and HTMLEditor which is usefull sometimes)
b) in the admin page enable the variable that allos the use of blocks in activity pages... then in the wiki turning the [blocks editing on] you can add a block named wiki-create a new page that allows to create a new page.
This secon strategy should be used alhong with the Page list block, because the new page will most likely be an orphaned page.
The admin block has a tool to keep track of orphaned pages.
See our doumentation and example wiki