Requirement:

I have to write a script that calls latest premium items on the home page of OpenCart from OsClass.

My directory structure:

OpenCart is installed on the root of website, and OsClass is installed inside classifieds folder in the root.

../public_html/ (OpenCart is installed here)
../public_html/classifieds (OsClass is installed here)

Website URL's:

www.example.com (OpenCart based main website)
www.example.com/classifieds (OsClass based Classifieds)

I basically need help from any senior, in finalizing the perfect method to get above requirement fulfilled.

Include this on the homepage of Opencart

<?php
require_once 'classifieds/oc-load.php';
$items = osc_query_item('premium=1');
// DISPLAY HERE $items AS YOU WANT
// print_r($items);
?>

Take a look at the function osc_query_item, you may want to modify the params to do display other items https://github.com/conejoninja/Osclass/blob/master/oc-includes/osclass/helpers/hItems.php#L1353