To upload a file in Aneuch, simply create a page. At the bottom of the page, you'll notice a link that says "Upload a file" (if uploads are allowed, see below). It will look similar to this:
Once you click on that, you'll be taken to the file upload page:
From there it's pretty straight-forward. Click the "Browse..." button, select the file that you want to upload, enter your edit summary, and click "Upload". That's it!
It should be noted that files, like regular wiki pages, are versioned, and a history is kept in the page database.
The following settings in your config.pl file dictate how and/or if file uploads are implemented on your site.
This variable sets whether or not files can be uploaded to the wiki. The default value is 0, which disables uploads, and is considered a sane default. Set it to 1 to allow file uploads.
This array holds the MIME types that can be uploaded if file uploads are allowed. The default is set to include 'image/jpeg', 'image/gif', and 'image/png', and is considered a sane default.