PmWiki offers a rich choice of options in the way of creating links between related notes as well as the use of the sidebar for accessing a collection of pages. In the Zettelkasten 'world', this similarly follows somewhat the idea of a 'hub' -- a sort of table of contents which assists in giving oversight in field of related ideas. Many persons find that a graphic environment is very useful in retaining an overview of ideas. With this in mind, the graphical mind-map environ offered, for example, by the app 'Freemind' can be good companion to PwWiki (for setup details see: b. Mind maps - Freemind)
In approaching any subject, the mind-map is handy for quick setting down of the main points as nodes in a map. Each node can then be linked thereafter to PmWiki pages via the Freemind's 'Ctl-k' dialogue through which the simple cut-and-paste of the page's link is made. The Freemind nodes can also be adorned with icons to make each node more memorable.
Entering http://localhost/ht those words will appear.
By creating other directories and html files within the 'ht' directory, such as 'images', 'docs' and even sub-sub-directories, PmWiki can load through such links other html pages which can be created to serve PDF files, even audio files and the like.