1. Download, unzip and copy "org.hotot.shorturl" tothe directory where hotot is installed (probably: /usr/share/hotot/ext).
2. Open the extensions page, enable "Hotot Short Url extension". Edit settings and select karmacracy como as your default shortener, and insert your login and 3rd party app key. You can find it in your settings > connections page
4. Press OK and have fun.