How to deactivate the webiste, please?

So, thanks to all input, i'm a lot further :lol:
But... I noticed the site is ONLINE! How can I take it offline and be able to take my time to work on it?
Thaanks.

Rename the public_html folder to public_html _old make a new folder public_html and upload index.html with the following text "site is underconstruction"

Thanks for reply.
Did so as you said, but now I would like to work in the offline version I have put in public_old.
However, in vShare Admin, I get error page. I know it is because of the link that has changed.
What can I do about it?
Thanks/