Is there a reason that you are using Plesk? Tools like that generally make support and management vastly more difficult. Something like a NodeBB install is so easy, but Plesk can make it so hard for no reason.
Thanks for your response!
So I would start writing the stuff... but I'm afraid it would be then limited to the functions that I'm using for my site, and of course some explanations depend on the theme that I'm using 😄