how do i integrate ccavenue payment gateway with my website in php

how do i integrate ccavenue payment gateway with my website in php

how do i integrate ccavenue payment gateway with my website in php.
$WorkingKey = "" ; //put in the 32 bit working key in the quotes provided
here $encResponse=$_REQUEST["encResponse"]; exec("java -jar ccavutil.jar
$WorkingKey \"$encResponse\" dec",$ccaResponse); $tok =
strtok($ccaResponse[0],"&");