This can be confirmed directory of files
https://www.youtube.com/watch?v=2vtft7XnUQY
1: You will save this plugin to plugin's folder
2: You will add to somewhere (e.g. top page) the following code.
<form action="./filesearch" method="get">
<p>
Keyword: <input type="text" name="q">
</p>
<p>
<input type="submit" value="Search">
</p>
</form>