Hi
You can edit the video module published in video position here the code to edit
<div class="video-shuffle-wrap">
<div class="video-shuffle" data-js-view="video-shuffle">
<div class="mask"> </div>
<video autoplay="autoplay" loop="loop" width="100%" height="auto" poster="http://www.cdu-badduerkheim.de/joomla32/images/stories/joomla/poster.png" style="width: 100%; height: auto;"><source src="http://www.cdu-badduerkheim.de/joomla32/images/stories/joomla/welcome.mp4" type="video/mp4" />
<object data="http://releases.flowplayer.org/swf/flowplayer-3.2.1.swf" type="application/x-shockwave-flash" width="100%" height="auto"><param name="movie" value="http://releases.flowplayer.org/swf/flowplayer-3.2.1.swf" /><param name="allowFullScreen" value="true" /><param name="wmode" value="transparent" /><param name="flashVars" value="config={'playlist':['http://www.cdu-badduerkheim.de/joomla32/images/stories/joomla/poster.png',{'url':'http://www.cdu-badduerkheim.de/joomla32/images/stories/joomla/welcome.mp4','autoPlay':true, 'controls': null}]}" /><img title="No video playback capabilities, please download the video below" src="http://www.cdu-badduerkheim.de/joomla32/images/stories/joomla/poster.png" alt="Sample Video" width="100%" height="auto" /></object>
</video>
</div>
</div>
Add the correct path to your Mp4 video