[Solved, tutorial.] How to change, edit, uploaded (from computer) web site?

Of “Deploys”, “Deploys” is (for me) “Production (No deploy message)”.

Clicking on it shows files of uploaded web site, at the very bottom of the page.

Yet, in section “Deploys”, “Deploys” is also “Need to update your project? | Drag and drop your project folder here. | Or, browse to upload.”.

Dragging a web site from a computer there, or uploading it by clicking “browse to upload” uploads it and then “publishes” if “Auto publishing” is enabled.

“Publishing” means the web site of olde to be replaced by the web site of newe.

For if “Auto publishing” is disabled, publish it by clicking newly uploaded “Production” which shall appear atop olde (above the old).

.

My note:
‘Tis now a tutorial for helpless for no-where I fould it.

I have uploaded a folder with a textual file containing my web site, surely it has “.html”.
It was not found, error 404.
To try fixing it - textual file I renamed to “index”.
Not a thing changed.
I fail to find any way to change the uploaded.

Confused I am of “Deploys”, “Deploys”, it weirdly opens place where are shown uploaded files, that place is of weird name (“Production”) and shows not that it will contain files and is, when not opened, seemingly combined with a section for uploading, as they are one.