How to attach a file without the user being able to explore all files?

This may give you some insight to what you want to do.

Implementing PHP File Upload Security

Thanks InsiteFX Ive recorded Implementing PHP File Upload Security for a later time in our project.

I now realize I wasnt thinking logically when I wrote the question. I am still in localhost in which case the website computer & the user computer/device is the same thing, whereas in reality they are different. Im trying to achieve the user being able to attach an advert file to a category file in the website computer & we dont want the user to have access to any files other than his/her own advert files, from which he/she should be able to select the file/advert of choice. When a user creates an advert it is stored into this type example folder - Adverts/user/drinks/coke.php - And we only want the user to have access to - Adverts/user/.. - nothing else.

We have categories similar to - Afghanistan/drinks - And would like a user to be able to attach a file/advert into a category file, which would be by the fwrite process sending the selected link such as - Adverts/user/drinks/coke.php

The HTML input type="file" now appears to be for only attaching a file from the users device to the website computer & not appropriate for our current exercise.

@InsiteFX do you know how I can get a user to attach a file in the website computer to another file in the website computer, & in PHP backend so that the function can not be hacked?