See this and notice the search boxes at top
https://drive.google.com/file/d/0B1_PFw--3o74YjVreHNBOWU2aEE/view
I just have a small form at top of the list page to search like
<div>
<form method="post" action="<?php echo DIR; ?>dog/indexadmin">
<label>sch</label><input type="text" name="psch" value="">
<label>Avail y or n</label><input type="text" name="aval" value="" size="10">
<input type="submit" name="submit" value="Search">
</form>
</div>
The search goes to a route which in turn calls a controller method to perform the search.
Make sure you are appending the querystring see the docs.