How to change number of items in a row Magento 2

I’ve been through topics like this:
Magento 2 change number of items per row

All of them claims, that if I wanna change my items row to display 4 instead of 5, then I would have to change in a file called _listings.less

Seems simple enough, but my issue appeared, when I discovered, that I am missing this file.

Actually my folder structure looks way different. I did a search all over my FTP to find the file, but it didn’t find it.

I am missing the web-folder in /public_html/app/design/frontend/Outline/outline6/Magento_Catalog

I’ve been looking around, but it seems that I need to find this file to do it officially, and not in an unrecommended way.

How can I move on from here?

I appreciate your time.