Wiki docs BEdita module using markdown syntax
Clone wikidocs module (or copy downloaded zip) into the modules folder inside BEdita root folder (like /var/www/bedita/modules), so:
cd /var/www/bedita/modules
git clone https://github.com/bedita/wikidocs.git
If something goes wrong take a look at log files (in bedita-app/tmp/logs) and tune your core.php file, changing debug level as needed (bedita-app/config/core.php).
Also read this article: http://docs.bedita.com/setup/if-something-goes-wrong-in-bedita