Refunded Partial Payment Through Paypal, but can't edit in the Admin on Zen Cart

I refunded a partial payment amount to a customer for an out of stock product, but I can't see anywhere to edit that in my zen cart admin area. It says edit on the customer's details, but when I go into it, I can only see the payment from paypal that I refunded, but I can't adjust the order in the store to make it accurate. Is there something I'm missing or just overlooking in there?

If you just want to make the customer's order history correct, there's this:

http://www.zen-cart.com/index.php?main_page=product_contrib_info&products_id=444

Thanks, I downloaded the edit orders to my computer, but I don't know what to do with the download. I didn't set up anything for my store in my file manager, I had a web designer do that. I only know how to deal mainly with the admin area to the store. I've never uploaded files before. I know at some point I need to learn how to back up my zen cart store files incase something goes wrong, but I'm in the dark about doing that too right now.