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
how to manage data for existing users who did not give consent? We had to remove all of their post?
In my case there are many users that aren't active anymore but wrote a lot of interesting messages. Removing their post would be disastrous.