There at least 2 easy way to create a page :

First one : Create a link in a page you are currently editing. For example edit the start page and add a link. If you use the default DokuWiki Editor you will write something like [[uploads:anewpage|the new page]] for the uploads user, make sure to include the allowed namespace uploads: before the page name.

Save the start page and look at it : you should read “the New Page written in red color. Click on it, DokuWiki will bring you ta this new page : you need to edit it and write something the save it to create it for real.

Second one: in your URL type the name of the page just after the php page : “doku.php?id=anewpage”