How to upload file

At a certain moment during my test I need to upload a file.
I have the File Uploader addon installed but it is not working for me.
Possibly I just do not understand how it works.
I go to the recorder to the page with the upload button.
There is a file input element, but it is not corresponding exactly with either the button or the test field.

I have the location in a parameter.
But when I use the step, nothing is happening.
The step passes, but nothing is uploaded.

What should I do differently?

I managed to get the OS native file search box open.
So I thought if I have focus on the fill in field of the OS Native search box, I will just send keys with the path, hit Tab a few times and use Enter. Just blind keystrokes, but nothing is happing there.