Ok, in docs it say that calendar is now a core function, so it no extra install 
And yes, in editor for post i can find a “calendar-button”
But i do missing the upcoming event calendar as normal calendar blocks for the actually month.
Also in edit post a way to choose - in which calendar it must come, as general, holidays, admins-only, .. …
Did i need any special “theme” for nice calendar functions?
You don’t need a special theme, but while it no longer needs to be installed separately, there are still a bunch of settings that can be set to configure the behavior of the plugin.
This topic is a good place to start exploring: Discourse Calendar (and Event)
It also links to a couple docs topics.
Hi mcwumbly ,
THX for replay ++ 
Here so its looking on my site…
But i have nowhere a “month” calendar with ALL events, missing also some buttons to set events to repeat weekly 14 days monthly… and also i find no calendar dashboard 
post is looking fine
But also on “post” users must can jump anyway to the “full-calendar”, to take a look what is before/after the event on the same day and all the normal madness…
But here this view, i can not find …
Can you tell us more about your current configuration of the plugin?
Which calendar settings have you changed? (/admin/site_settings/category/discourse_calendar?onlyOverridden=true)
The one I am most interested in is Discourse post event enabled
i can not find any path on “system or web” that do contents “/discourse_calendar”…
that’s why i still think on my server/app/install - is anything missing. 
BUT i am not a dev…
What’s your current Discourse version (or can you share a link to your site)?
sure, this is easy for me as noob “gg”
buschitut.eu is main website with tab “g2g”.
sure all apps runs anyway extern or on subdomains as discourse.buschitut.eu
in the next step i like to add a footer for category’s & topics, which do content an “accordion” to run for this category/topic_name the same name forgejo and matrix spaces, i THINK that will be an “handy” way to have “all on one place”…
You need to install the plugin (Install plugins on a self-hosted site)
It was recently merged into core, but since your forum is on the stable branch, that change does not yet affect your forum.
“yippee” so i have right, there is only missing a part after install
THX++
