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
