Copy and paste the /picowiki/ folder to your server. Boom, done.
Now you are ready to start creating and editing Markdown files in the /files/ folder.
You can optionally edit index.php and customize the Wiki's title and a few more settings.
Edit the favicon.png and style.css to match your branding.
Furthermore, the PHP code is less than 100 lines of code and pretty straight forward to grasp and extend.