@ron_jeremy thx for your suggestions how to improve the situation.
Sometimes this helps more than a pull request.
BTW pullrequest just means, that you could fix docs or add some missing informations.
If you don't know how to do it, we can help you. Or if you have like a chapter you would contribute but don't know how to add, just ask and we can add it for you.
The complete Plone docs are free and everybody can improve and use it.
Regarding the Installation, i had also some trouble, when i was guiding some one who was not using Plone at all before, to install it on his Ubuntu server. As we usually have the needed system libs alsready, the installation is very easy, but he didn't have this, so we needed some manuell steps and they where not so easy for him to find.
This could be improved.
But also the installer is a lot better now. I you just run it with out any options, it will give you the needed hints for the libraries. But if you run it with options like i always do, you will not have this .
So I think it's not hard to improve here, because in general the installation is not that complex. I simple how to install page should do the job. And I mean a simple one. Just run it and configure a Nginx in front of it. I think we have some good docs there, but maybe we should guide the users better to it.
And your suggestions with the user testing, is a really good way to test it and improve.
Regarding the forum, as Andreas sad, plone.app.discussion is not a forum, but you can use it like it for smaller things. But Discourse is of course a lot better for a forum and has way more interesting features for a forum. So as always it depends on your needs.
Personally a would almost every time go with a external forum, instead of a add-on inside a CMS. Because the user and developer base of this tool is usually bigger than for an add-on. But if you need a really deep integration with less effort, using internal tools like plone.app.discussion is worth a try.