DokuWiki recognises PDF and JPEG/GIF files. It is best to have them organised under the media directory. To do so, click on the media manager icon found on the top right corner of the page you are editing. When your hover your mouse pointer on these icons, a short help is displayed and the media manager icon says "Add images and other files". Once you click, the media manger window opens. Now click on the root directory (displayed on the left side of the media manager window). Click on "select files …" icon, and specify your file. Now prepend the displayed file name with "media:<YourDirectoryName>". This way all your media gets stored under YourDirectoryName.