Modify Add classified page HTML and Upload multiple photos.

Hello

I would like to allow user to upload multiple photos (Not using add media i want separate image upload section) to their classified post. Currently it's only allowing me to upload images using add media but its adding images to the_content().

Also i want to change http://website.com/classifieds/add-classified/
form html . i am attaching snapshot below. I tried to copy
/plugins/classifieds/ui-front/general/page-update-classified.php file and paste this in my theme folder and added
global $post, $post_ID, $CustomPress_Core;
$cf = $Classifieds_Core;
$classified_data = '';
this code and replaced all $this with $cf->
but after doing this form is not posting.

Can you please suggest how I should do this?

Thank you,
Eugene