Trying to duplicate Categories field for products

Hello everyone!

I am trying to create a new field for products in Opencart named "Collections".
I want this for my online bookstore, I duplicated the files, made all changes...where category was I duplicated that file and made "collection" like the category...but without succes. I have a vqmod file that shows the categories on product pages...that worked fine...but with collections it's not working...
please help me!

So, you already created everything, but no-one knows, around here, what you did,
and how you did it. So, what you expect someone to reply now ?
Ernie

IP_CAM wrote:So, you already created everything, but no-one knows, around here, what you did,
and how you did it. So, what you expect someone to reply now ?
Ernie

Yes, I know...but I did a lot of things and the only question is: how to duplicate the internal categories "module"?....not the one that is on Modules like a box with products...just another Categories-like "module"to create collections or authors.
I think the model files are the problem here.